Mario & Sonic at the Olympic Games Tokyo 2020

Mario & Sonic at the Olympic Games Tokyo 2020 is a sports game and the sixth installment in the Mario & Sonic series. It is based on the real-world, which takes place in Tokyo, Japan. This marks the first instance where the series skips an Olympic Games, as Ubisoft acquired the rights to develop video games before Sega could. It was initally announced on March 29, 2019, as one of Sega's new video games to be based on the 2020 Olympics. The game was formally revealed in Nintendo's E3 Nintendo Direct of 2019 and was released for the Nintendo Switch on November 1, 2019, in Asia and November 5, 2019, in North America. The game has also two companion games: an arcade version of the game that released in Japan on January 23, 2020, and a mobile game featuring only Sonic the Hedgehog characters that released on May 7, 2020. It is also the first Mario & Sonic game to be published by Sega in Japan and other East Asian countries, and the last game overall to be developed by AlphaDream following their bankruptcy on October 1, 2019.

Unlike in previous games, most characters wear appropriate sports clothing depending on the chosen event. Additionally, the game's title places the location and year (Tokyo 2020) after "Olympic Games" rather than before, while it is completely omitted from the logo in non-Asian versions of the game. 2D Events are introduced, which are events from the, use only button controls, and are based on older sports games, utilizing the 8-bit (Mario) and 16-bit (Sonic) styles. The game is the first home console installment to include a Story Mode, which takes place in both 2D and 3D.

Due to the, it was announced on March 24, 2020 that the 2020 Olympic Games would be postponed to a later date in 2021, which was later revealed to be July 23, 2021 to August 8, 2021. This causes Mario & Sonic at the Olympic Games Tokyo 2020 to have the longest gap between the game's release (November 2019) and the commencement of the actual Olympics (July 2021) out of any Mario & Sonic game. Despite the real world Summer Olympics being postponed to 2021, the game still honored and bore the "2020 Summer Olympics" title.

Quick Match
Quick Match is where the player can play any of the game's events with any of the playable characters. After selecting Quick Match, the player will first choose how many players are playing before selecting events. The CPU difficulty can also be set here, the options being "Normal," "Hard," or "Very Hard". Each difficulty has its own set of medals for each event.

Story Mode
This is where the player can play the game's single-player story. The story involves Mario, Sonic, Toad, Bowser, and Dr. Eggman getting stuck inside a video game based off of the Olympic Games of Tokyo 1964, and Luigi and Tails attempting to get them out, encountering various other characters on the way.

Local Play/LAN Play
Players can connect multiple Nintendo Switches, either through the Switch's local wireless functionality or through a local area network, to play together. Both Tokyo 2020 and Tokyo 1964 events are available to play in this mode, and the length of matches can be adjusted. Each player needs their own Switch and a copy of the game to play.

Online Play
The player can make rooms with up to four people in them and compete against them in events. Only Tokyo 2020 events are available in this mode and match length cannot be changed.

My Data
My Data contains extras that the player can look at:
 * Game Room: The player can play any of the minigames that have been unlocked in Story Mode. As the player progresses on through Story Mode, they will unlock more minigames.
 * Tournament Records: The player can view their personal and world records for each event and can also compare their scores on the world rankings.
 * Trivia: The player can read trivia on the Olympic Games, the events, Tokyo, or the playable characters. Trivia is found throughout Story Mode. There are over 100 trivia pieces.
 * Options: The player can adjust game options here.
 * Credits: After beating Story Mode for the first time, the credits can be viewed anytime in My Data.

Playable characters
Mario & Sonic at the Olympic Games Tokyo 2020 features a total of 32 playable characters. Similar to the Wii U version of the previous game, the 20 playable characters that have been playable since the second installment are playable in all events, while new characters and characters that debuted in the previous game are only playable as a guest in a single event. Guests are unlocked by beating them at their event in Story Mode, though unlike the previous game, not every event contains a guest character.

11 characters have been cut since the previous installment: Nabbit, Dry Bowser, Dry Bones, Birdo, Roy, Toad, Wave, Sticks, Omega, Cream, and the Miis, making this the first Mario & Sonic game to have fewer playable characters than its predecessor, as well as the first home console Mario & Sonic game not to feature Miis as playable characters.

The descriptions in the following tables come from the Story Mode party member descriptions for the main cast, and the trivia cards for the guests.

Supporting characters
These characters are playable in certain events, but are not selectable and, in the case of Football, have more limited functionalities than other characters. The teammate that is set to default depends on whether the team leader is from Team Mario or Team Sonic. The home/first team uses blue teammates while the away/second team uses red teammates. Oddly, the head icon for the red team's Birdo uses the color scheme of the character Birdo, while in-game, it uses a species of Birdo with the colors of her body and bow swapped.

Advantages
Excluding the 3DS version of Mario & Sonic at the London 2012 Olympic Games, this is the first Mario & Sonic game not to report the character stats. Instead, the game reports for each character specific advantages that correlate to their character type (All-Around, Power, Speed, Skill) from the first four games. All-Around characters do not have a specific advantage but are listed as "All-Around" in all events. This is the first Mario & Sonic game with character types to have an uneven amount of characters per type, with only five All-Around types, seven Power types, eight Speed types, and twelve Technique types.

Although not reported in-game, each character has advantages even within a specific type. Luigi, for instance, is slower and less powerful than Mario, but has better technical ability. The stats are the exact same as the previous installment (Toadette's stats are the same as Toad's from that game).

Referees

 * Charmy Bee
 * Cubot
 * Lakitu
 * Orbot
 * Toad

Cameramen

 * Toads
 * Chao

Other

 * Chao
 * Cheese
 * Cream the Rabbit
 * Cuckies
 * Flickies
 * Egg Pawns
 * Goombas
 * Koopa Troopas
 * Omochaos
 * Peckies
 * Pickies
 * Pockies
 * Shy Guys

Events
There are a total of 24 playable events in the Olympic Games Tokyo 2020, with 21 of them being Olympic Events and three of them being Dream Events. During Olympic Events, most characters wear proper outfits for the event, while during Dream Events, everyone (except for the female characters, who still wear their sport outfits) wears their standard outfits, in a similar fashion to previous games.

All of the events (with the exceptions of Boxing, Karate, Football, and Rugby Sevens) give players the choice of using motion controls (with either one of two Joy-Cons) or solely button inputs (on any controller). However, Discus Throw and Dream Shooting have mandatory uses of motion controls regardless of the player's setting. Boxing, Football, Rugby Sevens, and Karate solely utilize button inputs.

Playable characters
There are eight characters that are playable in the Tokyo 1964 events: four from Team Mario and four from Team Sonic. The Mario characters use their 8-bit sprites from Super Mario Bros. while the Sonic characters use their 16-bit sprites from Sonic the Hedgehog (or Sonic the Hedgehog 2 and 3 respectively, in the cases of Tails and Knuckles). Unlike in the Tokyo 2020 events, all characters have the same stats.

Supporting
In Volleyball, each character has five teammates that can be controlled by the player.

Referees

 * Toads
 * Lakitu

Cameramen

 * Toads

Other

 * Bloopers
 * Buzz Bombers
 * Cheep Cheeps
 * Cluckers
 * Cuckies
 * Flickies
 * Goombas
 * Hammer Bros.
 * Koopa Troopas
 * Mecha Sonic
 * Nebulas
 * Peckies
 * Pickies
 * Rexons
 * Rickies
 * Rockies
 * Shy Guys

Events
There are a total of 10 events that take place during the Olympic Games Tokyo 1964, introducing a new sprite-based variant of events called 2D Events. Unlike the 2020 events, 2D events feature unique commentary by an announcer during the event, with their commentary usually corresponding to how the character is doing in the event. The player also has the option to turn on "Analog TV", which causes the screen to appear like an old-fashioned CRT television screen. All of the Tokyo 1964 events solely utilize button inputs.

Chapter 1: A Mysterious Game System
Mario and Sonic have arrived at the Olympic Stadium, excited for the Olympic Games. A short while later, Toad arrives with a gift that is addressed to both Mario and Sonic. They open it to find a retro video game system inside with a letter that reads, "To Mario and Sonic with love, in commemoration of the Olympic Games in Tokyo! We made a little game to let you experience the past Olympic Games in Tokyo. By all means, give it a try!" While Sonic is trying to figure out who sent it, Toad mentions how retro it is due to it saying "Tokyo '64" on it. Since there is no name of who it is from, Sonic begins to get very suspicious of it. Meanwhile, Bowser and Dr. Eggman are hiding behind the sidelines, waiting for Mario and Sonic to turn on the system. After Luigi arrives, Bowser begins to get more impatient and decides to turn it on himself, despite Dr. Eggman's objections. When Bowser reveals himself, he scares Luigi, who was holding the system, causing him to drop it and press a button on it. When he picks it back up, the screen begins glowing, which causes Mario, Sonic, Bowser, Dr. Eggman, and Toad to all disappear.

Chapter 2: Dr. Eggman & Bowser's Scheme
In a heavily pixelated world, Mario, Sonic, Bowser, Dr. Eggman, and Toad all fall from the sky into an unknown location. After they notice their 8-bit/16-bit appearances and the environment around them, Dr. Eggman deducts that they were sucked into the video game, since whoever the light from the screen touches gets swallowed into the game. With Toad's help, Sonic figures out that the system was a gift from Bowser and Dr. Eggman, and that their plan was to get Mario and Sonic stuck in the game. Dr. Eggman created the game while a Magikoopa's magic allowed it to suck them in. However, their plan backfired since Bowser and Dr. Eggman got sucked in as well, with Dr. Eggman claiming there is no way out. Eventually, they realize from a nearby sign that the video game is based on the 1964 Tokyo Olympic Games (hence the name Tokyo '64). Dr. Eggman decides that he and Bowser should compete in the games, to Bowser's confusion, but he agrees regardless so he can win gold medals. They enter the National Stadium, with Mario and Sonic following shortly afterwards, having also decided to compete in the Olympic Games, much to Bowser and Dr. Eggman's shock. The first event is the 100m, in which Sonic manages to beat Dr. Eggman. After his loss, Dr. Eggman states that he and Bowser will train harder to win the Olympic Games.

Chapter 3: The Search for Tails
Following the disappearance of Mario, Sonic, Bowser, Dr. Eggman, and Toad, a frightened Luigi is left with nothing but the Tokyo '64 in his hands. After he tells a nearby Omochao what happened, the Omochao suggests to find Tails, who is knowledgeable about machines. However, he does not know where Tails currently is. Suddenly, Amy appears to compete in the 100m. She tells Luigi and the Omochao that she does know where Tails is, but since her event could not start due to a lack of competitors, she asks Luigi to compete against her in the 100m first. Luigi accepts her challenge and wins against her, and she tells him that Tails went to watch Karate. She joins Luigi as he goes to Nippon Budokan to find Tails. There, a red Toad informs them that Tails already watched matches and left, stating he had a promise to keep, but also tells them that he might have gone to the Gymnastics venue with Daisy. Luigi goes to the Ariake Gymnastics Centre, where he finds Daisy, who is anticipating the Floor Exercise event. After Luigi asks about Tails, she says they were going to Ariake together, but split up, with Tails going to another venue. Despite wanting to be focused on finding Tails, Amy competes in Gymnastics against Daisy regardless and wins. After Daisy's loss, she asks Luigi why he is looking for Tails, which also increases Amy's curiosity since she never asked either. After Luigi explains the situation, Daisy joins Luigi and Amy to find Tails. Luigi decides to go to the Ariake Urban Sports Park, where he finally finds Tails, who decided to compete in Skateboarding against Sonic, only for him to not attend. After a nearby Omochao announces that the event is about to start, Tails, who is unaware of Sonic's situation, asks Luigi to take Sonic's place. Luigi reluctantly agrees and beats Tails in Skateboarding. Afterwards, Amy and Daisy tell Tails of Mario, Sonic, and Toad's situation, and Luigi shows the Tokyo '64 to him.

Chapter 4: The Secret Trick
In the 1964 National Stadium, the Long Jump event is next, with Dr. Eggman leaving the victory to Bowser, only for him to lose it to Mario. After his loss, Dr. Eggman pulls Bowser to the sidelines. Bowser asks him why they are collecting medals instead of finding ways to return to the real world, and Dr. Eggman explains to him that the only way to escape the game is to collect gold medals, with his claim earlier about there being no way to return having been a lie to hide information from Mario and Sonic. However, Toad reveals that he overheard the conversation, and he relays the information to Mario and Sonic. They go to confront the villains to verify that they were not lying, but find that they managed to escape while Toad was explaining. A nearby Pecky tells Toad that Dr. Eggman flew westward, so Sonic decides to chase him, while Mario and Toad look for Bowser. While Sonic is looking for Dr. Eggman, he finds a Pocky standing next to his Eggmobile. After the Pocky tells Sonic that Dr. Eggman boarded a bullet train, he sees him on the train and chases after it. After beating the train to Tokyo Station, Sonic searches for Dr. Eggman, but does not find him and leaves. Eggman, who was hiding behind a tree, then declares that his plan to stall Sonic was a success and uses this time to find more venues to compete in. Meanwhile, Mario and Toad go to Sumida River to find Bowser. After seeing Bowser flee on a boat, Mario boards another boat and chases him on the lake. After intercepting Bowser's escape, he and Toad corner him at a dock, but when Toad enrages Bowser and hides behind Mario, they get distracted and talk about random things, which Bowser uses as an opportunity to escape. Eventually, Sonic arrives, and he and Mario both report that their villains got away and that they are probably meeting somewhere.

Chapter 5: The Lost Game System
Upon investigating the Tokyo '64, Tails discovers that Mario and Sonic are competing with Bowser and Dr. Eggman inside the game, which confuses Luigi and company as to why they would compete in such a situation. However, Bowser Jr. suddenly appears, declaring that only he is allowed to have fun, and takes the system from Luigi. Even after the group explains the situation, Bowser Jr. is still sceptical and leaves with the Tokyo '64 to find out for himself. After Amy suggests that they check other venues, Tails counters with the fact that they need passes to access them, and goes with Luigi to find some. They go to Tokyo Tower and find Silver there, who was sightseeing, and ask him about passes. He explains that he had passes for the Tokyo Aquatics Centre and the Aomi Urban Sports Park, but dropped them while he was climbing up the tower. Tails climbs the tower and obtains the passes, which Silver lets him keep. He also joins the party due to how serious their situation seems. With their pass, they go to the Aomi Urban Sports Park, where they confront Bowser Jr., who is being accompanied by Rouge. He still refuses to return the Tokyo '64, and Rouge, who sides with him, challenges Daisy to Sport Climbing, saying they will return the system if she loses, to Bowser Jr.'s dismay. After Daisy beats Rouge, they return to the ground and realize Bowser Jr. already left, deducing that he ran off to another venue. They track him to the Tokyo Aquatics Centre, where he is now being protected by Wendy. Silver decides to challenge Wendy to 100m Freestyle and wins. Wendy fakes being a sore loser to distract the heroes while Bowser Jr. escapes to find Eggman Nega. Luigi and Tails go to Nippon Budokan, only to find Bowser Jr. already there with Eggman Nega, who is intrigued by the device. Luigi decides to challenge Eggman Nega to Karate in order to get the system back and wins. Accepting defeat, Eggman Nega is ready to give the Tokyo '64 back to them, only for Bowser Jr. to intervene and tell him that he has to investigate it. Upon further investigation, Eggman Nega realizes the system is one of Dr. Eggman's creations. After Tails explains that Mario, Sonic, Bowser, and Dr. Eggman got trapped inside of it, Eggman Nega decides not to give it back, and leaves with Bowser Jr. to analyze the game further in order to to free Bowser and Dr. Eggman. Luigi and Tails resolve to find them before they free the villains and leave the heroes inside forever. As Luigi and Tails do not know where to find them, a nearby Omochao suggests getting help from Vector, who is competing in Discus Throw at the Olympic Stadium, and they go there in order to do so.

Chapter 6: Another Showdown
Mario and Sonic find Bowser and Dr. Eggman in the Tokyo Metropolitan Gymnasium. The villains are shocked, having thought that they had finally lost the heroes and could obtain all of the gold medals themselves. Although Dr. Eggman denies that there are any methods of returning to the real world, Toad arrives and tells the villains that he knows their scheme due to them having discussed it very loudly. After Dr. Eggman admits that what Toad heard is true, Sonic tells him he and Mario will not let the villains get the gold medals. Following this, Mario challenges Dr. Eggman to the Vault and wins, obtaining a gold medal. Bowser belittles Dr. Eggman for letting Mario win, but Dr. Eggman refutes, saying that the heroes will not know what to do with the gold medals after obtaining them. After Bowser realizes this, he begins laughing maniacally.

Chapter 7: Time for Analysis
At the Olympic Stadium, Luigi and Tails approach Vector, who is about to compete in Discus Throw and states that no one can beat him. After Luigi explains the current situation to Vector, he determines that it seems serious. However, in order to fulfill Tails' request of finding Eggman Nega and Bowser Jr., Vector requires them to either pay a fee or compete against him in Discus Throw and win, to which Tails accepts the latter. After Tails does so, Vector agrees to start the search for the two villains. First, he decides to get help from others to gather information. He notices Toadette in the distance and decides to enlist her aid in the search; when she is asked of the villains' whereabouts, however, she says that does not know since she just arrived at the Olympic Stadium. Vector invites her to join the party in their search, and although she thinks this would be fun, she was planning on competing in an event and wonders if anyone would like to challenge her, offering to help them afterwards. Silver accepts this request and competes against Toadette in the 110m Hurdles, which he wins. After Silver's victory, Vector orders everyone to split up in order to find Bowser Jr. and Eggman Nega and says he will reunite with Luigi and Tails later. Upon hearing this, the duo leave the stadium to begin their search. They ask a purple Toad at Tokyo Tower and an Omochao at Tokyo Station, with the latter suggesting that they may find Eggman Nega in the Tokyo Metropolitan Gymnasium. Upon their arrival, they discover that Vector already found them there, but that all three of them were too late, as Eggman Nega had already begun his analysis on the system. Bowser Jr. also gives them a precaution, saying they might erase the whole game (and thus the five characters inside) if they try to intercept the analysis. Eggman Nega brings out Zazz to have some fun with the heroes while they wait for his analysis to be complete, and Bowser Jr., wishing to be entertained, demands that Zazz competes with them; he agrees but claims he is doing so only for his own victory. To cure his own boredom, Vector decides to be the one to take on Zazz in Table Tennis and wins. Eggman Nega then declares he is mostly finished with his analysis and has found no way to free the trapped characters, much to the shock of everyone else.

Chapter 8: Under the Olympic Cauldron
Bowser and Dr. Eggman are still discussing what the gold medals are used for when Sonic appears next to them, trying to find out what they are talking about this time. Dr. Eggman lies that they are coming up with strategies for winning in the next event, and they then leave. Sonic determines that they cannot be trusted and leaves with Mario. The two manage to trail them to Nippon Budokan, where Bowser is preparing himself for the Judo event so that he may win a gold medal. Dr. Eggman believes that since Bowser is a heavyweight, neither Mario nor Sonic will be able to beat him, but Sonic is able to win regardless. After Bowser's loss, Dr. Eggman decides that they should split up for now and devise a new plan at an undisclosed location. Before they leave, Bowser teases the heroes by saying the gold medals will not be enough to get them out. Sonic becomes suspicious of this statement and tries to find the location at which the villains will meet. At the nearby Tokyo Roads, the two heroes reunite with Toad, who says that someone who looked like Dr. Eggman left in a red taxi. With his speed, Sonic chases after the taxi and manages to stop it before it can reach its destination; however, he then discovers that its passenger was actually a Picky who was "hired" by Eggman to impersonate him in the taxi (although he never actually got paid). After the Picky mentions a big flame, the heroes deduce the real Eggman's location and find him at the National Stadium, lurking in a hidden area in the sidelines with Bowser. They decide to stay and eavesdrop to find out what they are planning.

Chapter 9: Gotta Get the Golds
After Eggman Nega announces that there is no way to get Mario, Sonic, Bowser, and Dr. Eggman out of the game system, Vector encourages him to continue his analysis. Eggman Nega recalls Dr. Eggman mentioning that gold medals would have a special effect inside the game, leading everyone to believe that collecting gold medals will allow them to free the trapped characters. Bowser Jr. sees this as a challenge to collect as many gold medals as he can, with Tails and Luigi having the same goal, but Eggman Nega decides to stay at the gymnasium to complete his analysis of the game. Luigi and Tails start at the Olympic Stadium, where they encounter Espio. As Espio is initially sceptical of the situation Luigi explains to him, Tails persuades him that it is in fact the truth, and that they need gold medals. With the Triple Jump about to commence, Espio encourages them to go up against him to win a medal, which Amy volunteers to do. After she wins against him, Espio becomes disappointed in himself for losing in one of his best events and leaves to train harder, wishing everyone luck in their mission. With a gold medal in their hands, Luigi and Tails require entry passes to access more venues and go to the Shibuya Scramble Crossing to look for them, where they happen to find Yoshi. Yoshi explains to them that he was with some friends but lost all of them in the huge crowd, and he asks if they can help him find them. The heroes are initially hesitant to help, so Yoshi decides to give them some passes as a prize for helping him, causing them to agree to help. Using a pair of binoculars, Luigi manages to find all of Yoshi's friends. After that, Yoshi gives the duo the passes he promised, which are for the Yumenoshima Park Archery Field, the Sea Forest Waterway, and the Tokyo Metropolitan Government Building. After the duo gains them, Yoshi begins to question why they are entering events in the first place, to which Luigi explains the whole situation. Hearing it, Yoshi decides to join them, saying he can spectate events with his friends later.

With the new passes they have, the first place they decide to go to is the Sea Forest Waterway, where they encounter the sneaky duo Wario and Waluigi, who claim they are about to win the gold in the Canoeing event here. After Tails says that he and Luigi will get the medal, Wario and Waluigi taunt them, saying there is no one better than they are. After Luigi and Tails beat them in the canoeing race, they blame each other for the loss until Luigi intervenes by telling them they need gold medals. Hearing this, Waluigi devises a scheme to pretend to help them get gold medals and then steal them later, to which Wario agrees. Out loud, they tell Luigi and Tails that they will team up with them to get gold medals, saying they will be unbeatable if they do so. While they are happy they have more people, Luigi and Tails are also suspicious of them, and then begin wondering how Bowser Jr. is doing with his gold medals. The next place that they go to is the Yumenoshima Park Archery Field, where they encounter Bowser Jr. He requests to see their medals to see their progress, which he uses as an opportunity to steal the medals, stating he is too lazy to get medals by himself. He plans to take them to Eggman Nega and get all the credit for them until Vector steps in to stop him. Just then, a voice can be heard in the distance, wondering what is going on.

Chapter 10: A Message from 2020
Meanwhile, Sonic, Mario, and Toad are still snooping on Bowser and Dr. Eggman, the latter of whom reveals a secret compartment underneath the Olympic Cauldron, which holds 14 holes inside of it, which he calls keyholes. If gold medals are placed inside them, a secret code will be activated, allowing the user to return to the real world. However, they are unaware that the three heroes have been listening the whole time, and they shock the duo with their eavesdropping. Accepting that the secret is out, the villains make it their mission to get more gold medals than anyone else, and go to another venue. Determined to win against them in medal count, Mario and Sonic meet them once again, this time at the National Gymnasium. After seeing their arrival, Dr. Eggman challenges his nemesis Sonic to the 10m Platform. However, the hedgehog wins over him, adding another gold medal to the heroes' count as Toad congratulates Sonic on his win. While Bowser tries to encourage Eggman that one loss will not stop them, the doctor notices something strange happening around them. He notices a giant screen overhead that initially begins fumbling around with random characters before finally reading, "POWER-UP ITEMS on their way. NEGA." When this happens, all five characters realize that something is happening.

Chapter 11: The Items' Sender
Back at the archery field, the voice in the distance while Vector and Bowser Jr. were arguing reveals herself as Peach, who begins to belittle Bowser Jr. because his noise is distracting the Archery competitors. Bowser Jr. requests to see Peach's medals, and the princess is about to show them to him until Tails steps in and tells her not to do it, otherwise he will take them. Luigi explains the entire situation to Peach, and she reaches a compromise that she will compete in Archery and use all of the gold medals that everyone has collected to save Mario and Sonic, to which Bowser Jr. reluctantly agrees. Daisy volunteers to compete in Archery against Peach, who is delighted to have an opponent to face. After Daisy's victory, Bowser Jr. wants to take the gold medal that she won just to save his dad, not caring about competing at all. Peach then starts telling him that they should work together and not take the medals that people work so hard to earn. After hearing this, and with much hesitation, Bowser Jr. gives all of the medals back to Luigi before running off. Once he is gone, Tails wonders what to do next, realizing that he has no more passes, until Peach reveals her pass to the Olympic Boxing Centre. Tails decides to go there since he believes he can deliver a good boxing match, and Peach joins the group due to wanting to save Mario and Sonic.

Once the party reaches the Olympic Boxing Centre, they find out that Bowser Jr. is already there and negotiating with Zavok to win the Boxing match for him. Zavok, who only wants to punch someone in a match, agrees to let Bowser Jr. take the gold medal once he wins. Luigi fearlessly decides to face off against the mighty Zeti, despite Tails' warning of his strength. Even with all of Zavok's strength, he still manages to lose against Luigi. After he fails to accept his defeat and flees, Tails suggests that everyone, including Bowser Jr., goes back to Eggman Nega with all of the medals that they won to see if anything new has come out of his analysis. Everyone heads back to the Tokyo Metropolitan Gymnasium, where Eggman Nega is laughing at the mistake he made in his analysis. He reveals that while his statement about collecting gold medals to escape was true, what he got wrong was that the gold medals are supposed to come from the game, not reality. Bowser Jr. begins getting upset at this, knowing that his dad and Dr. Eggman always lose against Mario and Sonic, and Eggman Nega, who is part of Eggman's family, acknowledges Eggman's failure, being disappointed at his ancestor. Because of this, Eggman Nega reveals that he decided to send some special power-up items to him and Bowser within the game that can affect only those two in order to make their victory more likely. Just when he is ready to send them out, Bowser Jr. becomes impatient and carelessly begins pushing random buttons on Eggman Nega's console, which causes the power-ups not to be sent to the proper location.

Chapter 12: The Scattered Items
Several mysterious items begin falling from the sky into various parts of 1964 Tokyo. Once Eggman realizes that Eggman Nega has come to assist them in the game, he begins laughing evilly, stating how he was able to alter the game's programming to send items to him and Bowser. With this, Eggman now knows that he has to use the power-ups to get gold medals to get out of the game, so he and Bowser disband to find the various power-ups lying around the 2D Tokyo. Knowing that they cannot stand a chance against them if they get hold of the power-ups, Sonic and Mario leave to go find the villains and stop them from taking them. At the Tokorozawa Shooting Range, they find Dr. Eggman, who has already managed to get hold of one of the power-ups, which is a piece of sushi that he dubs the Miracle Roll. He consumes the roll and, although it was tasteless, feels the power that the roll gave him, stating that everything about him has been amplified. However, Sonic believes that, even with the power of a Miracle Roll, he can still beat Dr. Eggman any day. To prove this, Mario challenges Dr. Eggman to the Shooting event that is going on here. Sonic's claim becomes a reality when Dr. Eggman loses the gold medal to Mario despite his possession of the Miracle Roll. Thinking that more of them will help him, Dr. Eggman flees the shooting range, while Sonic also realizes how bad it could be if Bowser got hold of the Miracle Rolls.

As the heroes go to find the Miracle Rolls before the villains can, they meet Toad at the base of Tokyo Tower, and he states that there is a light shining from the top of the tower, which he believes is one of the Miracle Rolls. Mario wants to climb the tower, but Toad stops him because Eggman's robots are all guarding the tower, making it very dangerous. To solve this problem, Mario strikes from the sky with an airplane while Sonic stands on top of it, with Mario using lasers to deal with the robots as well as Eggman himself, who is in his Eggmobile. Once the heroes acquire the Miracle Roll, they land back on solid ground, but Toad warns them that Eggman and his robots fled to other Miracle Rolls, so they make it their mission to stop them from getting any more Miracle Rolls. They head to the Museum, but they are blocked at the entrance by a group of Toads, who say that a Miracle Roll fell from the sky and ended up on the fourth floor of the Museum, and that the Koopa Troop has seized the Museum while kicking the Toads out, in order to keep it under lockdown until Bowser arrives. Not wanting to let Bowser get the Miracle Roll, Mario sneaks through the Museum past all of Bowser's guards to get it himself, and after he succeeds, all of Bowser's minions leave out of fear that Bowser will punish them for their failure. With Sonic wondering about the roll being tasteless as Eggman said, Mario gives it a try for himself, confirming Eggman's statement as well as the fact that the power-up has no effect on him, meaning they cannot get any power from them, but they can still keep Bowser and Eggman from getting them.

Chapter 13: The Excitement Battery
Because of Bowser Jr.'s random button pressing, Eggman Nega's power-ups have been scattered all around the game land. When Tails asks if he can have the game system back, Bowser Jr. refuses until his dad and the doctor manage to get out, and says that if they want it back before then, they should compete against him at the Olympic Stadium, which is where he runs off to with the Tokyo '64. When the party arrives at the Olympic Stadium, Bowser Jr. promises that if they can beat him, they can have the system back. Having wanted to take on Bowser Jr. for a long time, Vector steps up and defeats the young Koopa in the Javelin Throw event. After Bowser Jr. throws a brief tantrum and runs away, Eggman Nega, who was watching the match, finally decides to give the game console back to Tails and Luigi. However, when he gives it back, Tails realizes that the red light on the side of the console is flashing, meaning that the system is running out of battery. Vector and Tails deduct that if the battery goes out, the five characters inside will be gone and unable to escape. Eggman Nega teases Tails for realizing this only now, as he had known for a while, and had made a device called the Excitement Battery, a battery powered by Magikoopa's magic, allowing it never to lose charge once it is filled up. Thinking that the Magikoopa should be done applying magic on it, Eggman Nega reveals that the Magikoopa is to be at the TOKYO SKYTREE with the battery, so Luigi decides to go there with Tails while Vector and Eggman Nega stay at the Olympic Stadium to keep watch of the console as it runs out of battery.

At the TOKYO SKYTREE, Luigi and Tails find out that Magikoopa had given the Excitement Battery to Larry, who does not believe the hero duo when they say that Eggman Nega sent them. Angered by them, he summons an army of Shy Guys to take care of them. After Tails fights off every single one of them, Larry becomes frustrated and still refuses to give up the battery, and he ends up running away, saying that they have to find him if they want it. After he runs away, Luigi realizes that he dropped three entry passes on the ground, allowing them to get into three new venues: Musashino Forest Sport Plaza, Tokyo Stadium, and the Equestrian Park. They find Larry in the Equestrian Park; annoyed at them, he once again refuses to give them the battery, but he begins to get confused when Peach mentions that the battery is needed to save Bowser. He then decides that if they want the battery, they have to win against him in an event. While Tails believes the young Koopaling will backstab them, Peach takes on his Equestrian challenge. Once she defeats Larry in the event, he finally accepts his defeat and gives the battery over to Luigi, at which point he reveals that the battery has to be charged before it can be used, but that he doesn't know how to charge it. Luigi then notices something happening with the battery, so he holds it up in the air, and the once-empty battery fills up slightly, much to everyone's surprise. While Larry leaves, Tails and Peach deduct that it is called the Excitement Battery because it fills up with the excitement and cheers of the audience, a function it gained from Magikoopa's magic. Tails decides that they need to compete in events to get the crowd's cheers up and get the battery completely filled so it cannot run out. With that in mind, he and the rest of the gang go to other venues to begin charging the battery.

Chapter 14: The Flickering World
Mario and Sonic end up finding Bowser at Lake Sagami, where they see that he has already gotten hold of another Miracle Roll, but before he can consume it and gain its power, a bird comes out of nowhere and steals the roll. Despite this, Bowser says it will not make a difference as he already ate two of them prior, much to the surprise of Mario and Sonic. However, Sonic claims that two rolls will only make things equal and he manages to win against Bowser in a Kayak race. Angry at his loss, Bowser regrets not eating the third Miracle Roll sooner and leaves to find Dr. Eggman and check on his progress, while Mario is worried about how much Eggman might have powered up and goes after him with Sonic. They find the two villains at the National Stadium, where they are discussing their status, and when Mario and Sonic decide to challenge them to test their power, Dr. Eggman decides to race Mario in the 400m Hurdles. As usual, Dr. Eggman loses against him, but he does not worry as he believes that he can directly ask Eggman Nega in the real world to send more powerful items. While he is calling out for Eggman Nega to do so, everything around the characters begins flashing on and off. Eggman quickly deducts that this strange phenomenon is in fact the game system's power running out of battery, surprising everyone else.

Chapter 15: Cheer Power
After learning how the Excitement Battery works, Luigi and Tails go to other venues to charge it via the crowd. The first place they go to is the nearby Tokyo Stadium, where they find Diddy Kong, who asks if they are here to watch. After Tails corrects him by saying they are playing, Diddy Kong reveals that he is as well, so Wario steps up to face him in Rugby Sevens as he claims that it is his time to get a gold medal. Wario and his team of blue Boom Booms manage to outplay Diddy Kong and his red Boom Booms. Thanks to the crowd cheers, the Excitement Battery charges a little more. Diddy Kong suggests that they go to the Musashino Forest Sport Plaza nearby. There, they come across two of Sonic's rivals, Knuckles and Shadow, both of whom know the gist of the whole situation that is going on. To help them charge the battery, the hedgehog and echidna take to the Badminton court together to please the crowd in a Doubles match. Peach and Yoshi team up as the two that will take them on. After they manage to win against Shadow and Knuckles, the battery charges even more. Knuckles is upset at his loss while Shadow claims he would have won if it was just him. Knuckles decides to join Luigi and Tails' crew to help them while Shadow also joins them and advises them to stay focused to the end. Knuckles then remembers that Jet, another one of Sonic's rivals, was searching for Sonic at the Olympic Stadium. Tails decides to go there to tell him what happened while Shadow tells them to be careful of him as he seemed to be worked up. After traveling back to the Olympic Stadium once again, the gang realizes that Jet is nowhere to be seen. Suddenly, Jet pops out of nowhere and orders them to stay away from the field because of the Football match that is about to happen. Jet then wonders where Sonic is because he promised a penalty kick shootout with him. Luigi explains the whole story, which Jet does not believe, and Tails states that they need to charge the battery. Knuckles then decides to take Sonic's place in the shootout and face Jet instead in order to excite the crowd. Knuckles wins against Jet, who blames only luck for his loss. The battery fills up even more, but Tails realizes they are out of passes again and wonders what they will do.

Chapter 16: The Time Remaining
After Dr. Eggman realizes that the battery for the Tokyo '64 is running out, Sonic wonders what will happen to them if it runs out. Bowser initially thinks that they will be stuck inside forever with no way to escape, but Dr. Eggman corrects him by saying they will vanish from existence, shocking everyone else. After panicking at what might be their fate if they are too late, Bowser, in an attempt to win more gold medals to escape with, challenges Mario and Sonic to a Volleyball match. Sonic and Mario decide that they have no choice but to accept his challenge in order to get out, and all four characters head to the venue where Volleyball is being held: the Komazawa Olympic Park General Sports Ground. There, Dr. Eggman presents to the heroes his elite team of Eggrobos, which he dubs Team Eggman. Sonic decides to take him on with his team of Pockies, and they manage to defeat Eggman and his robot gang. Eggman becomes angry, but Bowser reassures him that they can win in the final event: the Marathon. In addition, he tells him that there is something else they can do even if they lose, confusing Mario and Sonic, though when Sonic asks about this, Eggman claims that they were discussing how to win the Marathon. After Bowser gloats about his stamina, both villains leave to go to the starting point of the Marathon, the National Stadium, so Mario and Sonic follow them.

Chapter 17: Charging Complete
After Jet wishes Luigi and Tails luck on their mission, the duo goes around to find someone with more passes so that they can get into more venues. On the search, they go to the Tokyo Metropolitan Government Building, where they happen to find Donkey Kong, who explains that he is there because he wants to see the view from the top of the government building, but that Metal Sonic and a group of Egg Pawns are in the way. After Luigi asks him if he has an entry pass, he reveals that he has a pass for Makuhari Messe Hall B, and when he asks why it is needed, Luigi explaibs the situation to him. Tails strikes a deal with Donkey Kong that he and Luigi will deal with the robots and, in return, Donkey Kong will give him the pass, and Donkey Kong accepts. Fulfilling his promise, Luigi uses his rugby skills to deal with the Egg Pawns on the ground and strike Metal Sonic, who is flying in the air above the building. After Luigi deals with them, Donkey Kong happily gives the duo his pass as he promised, and he also decides to join them because he thinks that watching them compete in events will be fun, deciding to go to the observatory later. The group goes to Makuhari Messe Hall B, where they find another Koopaling, Ludwig, who has been told by Larry that Luigi and Tails stole Magikoopa's battery from Larry, so he has a grudge against them. Tails explains the truth to Ludwig, and Luigi brings out the Excitement Battery to show him, which Ludwig uses as an opportunity to steal it from them and throw it to Wendy, who successfully catches it. The two Koopalings keep the battery for themselves to give back to Larry, until Ludwig gets the idea to have a competition for the battery, stating that whoever wins gets to be the owner of it. Waluigi accepts Ludwig's challenge, wanting to compete in order to obtain both the Excitement Battery and a gold medal. Ludwig likes Waluigi's attitude and the two of them go against each other in Fencing. However, just like Wendy and Larry before him, Ludwig ends up losing the match. While Wendy is belittling her older brother, she takes out the battery. The battery begins glowing, which scares her, causing her to accidentally throw it in the air. Luigi catches the battery, and it charges up even more. After learning how the battery works from Tails, the two Koopalings let Luigi and Tails keep it since Wendy does not want to do work while Ludwig does not want to get involved in anything that he considers weird, and they both leave.

While walking around to find someone with more venue passes, Luigi and Tails find Blaze at the Kabukiza Theatre, where she was intending to watch a between Olympic Events, but found that the entrance was being guarded by a group of Egg Pawns. She explains that she wanted to use her fire powers to destroy them but worried that she would set the theatre on fire as well. Luigi asks for an entry pass from her, and she reveals that she has one for Tsurigasaki Surfing Beach, so Tails sets a deal that he can clear the Egg Pawns if Blaze gives the venue pass she has, which she accepts. Tails shoots down all of the Egg Pawns with a bow and arrow, and Blaze gives him and Luigi the pass as promised. Tails offers for Blaze to join the party, and she accepts in order to help save Mario and Sonic. The group then goes to Tsurigasaki Surfing Beach, where they find Rosalina, who is aware of the activities that Luigi and Tails are engaging in. To help them charge the battery, Rosalina decides to hold a Surfing competition to get the crowd cheering. Donkey Kong is reminded of his own island upon seeing the ocean, and Rosalina asks if he wants to be in her competition, which he accepts. After he beats her in the competition, the battery becomes fully charged, allowing it to be used without ever recharging it.

Chapter 18: Heading Back
Taking on Bowser and Dr. Eggman's challenge in the Marathon, Mario and Sonic go to the National Stadium to meet them. There, they find many competitors who are running in the big race, including Toads, animals, and Hammer Bros, and Toad is present as well. When Bowser and Dr. Eggman find the heroes, Bowser begins gloating about how this event requires a lot of stamina to win, which is what he has. Mario decides to partake in the race with his arch-nemesis to win the gold medal. A nearby Flicky lets everyone know that the race is beginning, and Mario and Bowser go to face off against each other. Mario successfully beats not only Bowser but also the 66 other competitors in the race. Bowser is angry at this result, but Dr. Eggman reminds him that they can still initiate their secret plan, which involves knocking out Mario and Sonic and stealing their gold medals. Bowser manages to do the former, but when he attempts the latter, he realizes that they do not have their gold medals. Toad reveals that he was the one holding on to their medals and gives them to Sonic after he and Mario wake up, stating they did not use just stamina but their brains as well. While Dr. Eggman tries to come up with a new plan, Sonic reminds him that they do not have much time left because of the battery, with Mario following up, saying that they should team up to get out. After Bowser and Dr. Eggman discuss how they can simply have a showdown when they return to the real world, they agree with Mario and Sonic. The five characters go to the Olympic Cauldron and place all of the gold medals into the keyholes. Initially, nothing happens, but then the medals begin to glow and everything around them starts shaking. A beam of light shines from the sky onto the flame which will take the characters back to the real world, but while this is happening, everything around them begins to flicker again. Eggman realizes that the battery has finally run out, stating that their mission was a failure despite them being so close to the goal.

Chapter 19: Battery Replacement
Tails and Luigi return to the Olympic Stadium, where Eggman Nega and Bowser Jr. are waiting with the Tokyo '64. With the battery almost dead, Tails and Luigi have to switch the batteries instantly, or else they will fail. Meanwhile, inside the game, Bowser feels something wrong with his body, with his speech also being affected, and when Dr. Eggman tries to run, he barely moves. He, Mario, Sonic, Toad, and Bowser all attempt to run in order to try to reach the light, but to barely any avail. The environment around fades away and becomes completely black. As they continue their attempt to reach the light, Tails pulls out the old battery from the system while Luigi puts in the new one. In the game world, Toad becomes the first one to fade away into nothing but a singular pixel. He is then followed by Bowser, Mario, and Sonic, who also become a singular pixel each before Dr. Eggman joins them as well. The five lone pixels then all disappear, meaning they would be gone, until all five regain their forms and the environment becomes colorful again, as Tails and Luigi's operation in the real world was a success. Tails, Luigi, Eggman Nega, and Bowser Jr. then celebrate in the real world. Mario, Sonic, Toad, Bowser, and Eggman all stand inside the beam of light. Luigi, Tails, Bowser Jr., and Eggman Nega watch from outside the console as five colorful figures exit the system, revealing themselves to be the trapped characters, who have returned to reality.

Final Chapter: The Final Showdown
Tails and Luigi welcome Mario and Sonic back to the real world, while Bowser Jr. and Eggman Nega reunite with Bowser and Dr. Eggman. Bowser praises his son for being brave and rescuing him while Eggman commends Eggman Nega for making the Excitement Battery to bring them back. After being stuck in the game for so long, Sonic notes how his movements feel restricted, which is very prominent in Toad, with both his movement and speech being very "blocky" from the game, though he thinks he will return to normal soon. Mario laughs at this while Sonic finds it weird. Bowser and Dr. Eggman then approach them, not forgetting the promise about settling things in reality. The event that is about to happen is the 100m. Mario, Sonic, Bowser, and Dr. Eggman enter as four of the sprinters, and Sonic offers Shadow to join as well, which he accepts due to wanting to show his ultimate power. Luigi and Tails then decide to join since they have worked hard on this mission from the start. Yoshi joins as the eighth sprinter. The final showdown in 100m then takes place, with the player being able to choose between Mario or Sonic to compete in the event. Mario or Sonic wins the final match, and with it completed, everyone celebrates. Mario and Sonic are seen running along the track and high-fiving, Peach and Amy are seen waving to a crowd, Bowser Jr. is seen having a tantrum on the ground before being comforted by Knuckles, Yoshi gets excited while Shadow walks away, Daisy and Blaze are talking into a camera, Bowser and Dr. Eggman are mad at their loss, but get over it quickly, Vector and Donkey Kong show off their strength, and Luigi and Tails high-five each other before one last shot of Mario and Sonic is shown. An 8-bit Mario then appears and hits a block, creating a highlight video accompanying the credits as they play. After the credits, the video turns into a sign from the original Sonic games and a 16-bit Sonic runs past it.

After the final chapter, the characters (besides Luigi and Tails) return to the areas where they were first encountered (except for Bowser Jr., who stays at the Olympic Stadium, and Larry, who returns to the Equestrian Park while a red Toad takes his place at the TOKYO SKYTREE), as Toad explains; if Luigi and Tails speak to the characters, then they can rematch them in their events or replay their minigames (in Tails' case, he can be rematched in Skateboarding if Luigi goes to the Ariake Urban Sports Park and speaks to him there). Bowser stays at the Olympic Stadium and can be spoken to to replay the final 100m race, while Dr. Eggman also stays at the Olympic Stadium and, when spoken to, allows the player to go up against him in the 4x100m Relay, in which he teams up with Metal Sonic, Bowser Jr., and Bowser, while the player uses Luigi, Mario, Tails, and Sonic. Additionally, the Dream Racing Arena, Dream Karate Coliseum, and Dream Shooting Range all open, where the player can play Dream Racing, Dream Karate, and Dream Shooting, respectively, all as Luigi.

Mario and Sonic also stay at the Olympic Stadium, and if they are spoken to, Sonic reveals that they can now freely go in and out of the Tokyo '64, which they use as an opportunity to participate in the Olympic Games again; however, Bowser and Eggman decide to go as well in order to get revenge on them in the events. Sonic asks Luigi to turn the Tokyo '64 back on; if he agrees, then Mario, Sonic, Bowser, Dr. Eggman, and Toad are sent back into the Tokyo '64, allowing Mario and Sonic to rematch Bowser and Eggman in events and minigames, while Toad stays at the base of the Olympic Cauldron and can be spoken to to return everyone to the real world.

Game Room
The Game Room is where players can play the minigames that are played during Story Mode. To unlock them for the Game Room, the player must beat the minigame in Story Mode first. There are 10 minigames that are playable; five 2020 minigames, where the player plays as Luigi and Tails, and five 1964 minigames where the player plays as Mario and Sonic in their 2D forms.


 * Kabukiza Clash: A horde of 36 Egg Pawns are standing in front of Kabukiza Theatre. Tails has to shoot them down with an Archery bow and arrow before they throw spiked balls at him. If he gets hit three times, he loses.
 * Shibuya Scramble Search: In a large crowd of Toads and Shy Guys in Shibuya, Luigi has to use binoculars to find four specific Toads, some of which are holding a specific item.
 * Treeside Rumble: Tails must fight 60 Shy Guys, while avoiding the spiked balls they throw. If he gets hit three times, he loses.
 * Tokyo Sky Flight: Mario is flying a plane while Sonic is standing on top of it, and Mario shoot the enemies that he encounters. When he reaches Tokyo Tower, he must take down Dr. Eggman, who fights similar to his appearance in Sonic the Hedgehog. If the plane takes five hits, the player fails the minigame.
 * Bullet Train Blast: Dr. Eggman is sitting inside of a bullet train, and Sonic must race it to its destination. While running, Sonic must avoid spikes, which will slow him down. Along the way, he can collect Monitors which have invincibility and shield power-ups.
 * Sumida River Boat Ride: Mario races Bowser on a boat. While racing, he must avoid Cheep Cheeps and other boats while jumping waves in order to beat him.
 * Highway Chase: Sonic is running on a road and must catch up to Dr. Eggman's taxi before time runs out. While running, he must watch out for other cars and banana peels while stepping on dash panels to speed up. When he reaches the taxi, he has to attack it to inflict damage.
 * Museum Sneak: Mario must sneak through four floors of a museum to reach the top. On each floor he must find a certain amount of keys to open doors. Throughout each floor, various Goombas, Koopa Troopas, Cheep Cheeps, Bloopers, and Hammer Bros. are searching for Mario, and he must avoid their lines of sight in order to not get caught.

In-game trivia
Throughout Story Mode, there is plenty of trivia that the player can obtain. When the player enters an area, there will be trivia cards scattered around the locale that will talk about various subjects including the Olympic Games, the events that are playable, the various venues and locations in Tokyo, and all of the playable characters in the game. Some trivia cards are only accessible after beating a character in a match or completing a minigame task. Additionally, there is a Green Toad in each area that can be talked to to receive another trivia question. There are separate sets of trivia cards for both 2020 and 1964, which are found in the various areas of those respective eras.

Differences from previous installments

 * The game's non-Asian titles place the location and year (Tokyo 2020) after "Olympic Games" rather than before.
 * The location and year are absent from the non-Asian logos.
 * Characters have unique outfits between events.
 * The game does not report the individual stats for each character, instead displaying what advantage they have in the event.
 * Several changes made in the Wii U version of Mario & Sonic at the Rio 2016 Olympic Games were changed back:
 * All features of the game are accessed in a menu rather than a hub world.
 * Characters have actual animations on the character selection screen rather than just using their artwork.
 * The announcer does not announce the character and the medal they won during the award ceremony.
 * The special pair animations from the Sochi and Rio Olympics do not return.
 * Getting 2nd or 3rd in one of the team events (4x100m Relay, Football, or Rugby Sevens) shows the characters wave during the award ceremony rather than clap.
 * Losing a 1-on-1 event (like Karate or Boxing) does not show the award ceremony player in 2nd place like in previous games, instead going straight to the menu. Because of that, Eggman Nega, Ludwig, Zavok, and Zazz's 2nd/3rd place animations can only be seen by losing a match online.

Announcement trailer

 * The head icons were recycled from the previous game before using newly designed icons for the final game.
 * In Skateboarding, the strips have a different design than the final game.
 * When the game shows how to do a Super Trick in Skateboarding, it only shows to press the "R" button, while the final game instructs pressing "A" and "R".
 * One scene of the trailer shows Mario and Sonic versing Luigi and Peach in Badminton. In that shot:
 * Luigi and Peach's Super Gauge had a placeholder label that says "no label", but mirrored. This was fixed in the final game.
 * The head icons for the opposing team were on the left side of the Super Gauge before being moved to the right in the final game.
 * In UI showing the score, both teammates head icons are shown next to their score. In the final game, only the leader's head icon is shown there.

E3 2019 trailer

 * In one of the scenes showing off Football, one of the Egg Pawn goalies were orange, while the final game replaces them with the red Egg Pawns instead.
 * The UI for showing the time in 2D 100m is different than the final game.

E3 demo

 * The title screen did not have Mario and Sonic on it.
 * The event and character selection screen used a different arrangement than in the final game.
 * The videos showing the events on the event selection screen are different than the final game, only showing the six characters that were playable in the demo.
 * Sonic's voice clips on the character selection screen were different in the demo than in the final game. His quotes in the demo were, "Yeah, time for some speed!" and "Aww yeah!", but were changed to, "Speed time!" and "Time for some fun!" The quote, "Born to do this!" is kept in the final game.
 * The CPU characters' flags were their standard flag, while the final game used real-world flags instead.
 * The environment during the award ceremony had different lighting effects between the demo and the final game.
 * Characters did not vocalize during their award ceremony animations. This was changed in the final game, making it more consistent with previous installments.
 * The label underneath the character during the award ceremony did not have the player's flag on it.
 * The menu that would follow the award ceremony did not have tips on it.
 * The music that played when setting a new record was the "London Party is Over" fanfare from Mario & Sonic at the London 2012 Olympic Games, before switching to a new fanfare in the final game.
 * The announcer did not say, "New Record" when setting a new record.
 * In 110m Hurdles, the announcer did not say, "On your mark," at the beginning.
 * No music played during the replay of 110m Hurdles or when characters were shown their results in Surfing. These were both changed in the final game.
 * Peach's 1st place animation had her hold a pose at the end. In the final game, after the pose, she starts waving to the crowd.
 * In Karate, the announcer had three different voice clips: 「始め！」 (Hajime!, "Begin!"), to begin the match; 「待て！」 (Mate!, "Wait!"), after an opponent was knocked down; and 「止め！」 (Yame!, "Stop!"), when the match was over (which matches real-life karate). For unknown reasons, the final game removes the "Mate!" clip and "Yame!" is used for both "Wait!" and "Stop!".

Unused data

 * There are voice clips of the female announcer calling the characters' names found in the game's files, but they go unused in the final game. They were most likely to be used during the Award Ceremony, where the announcer would call the character and the medal they won, similar to previous games. Additionally, there are two variations for each character, and these files contain variants for several characters who have different names in Japanese (e.g. Bowser as Koopa, Rosalina as Rosetta) as well. This property also applies to Yoshi as well, unlike other games with similar announcer calls, with the announcer pronouncing the "O" slightly shorter.
 * One of these unused voice clips has the announcer calling for Zeena, one of the main antagonists from Sonic Lost World alongside Zavok and Zazz, suggesting that she was planned to be playable at one point. This meant that either there were going to be seven guests from each series instead of six (with the seventh Mario guest being unknown) or Zeena was to be playable instead of one of the characters currently in the game. Furthermore, her announcer calls are located between Zazz's and Rouge's, implying that she was considered as a guest character rather than being part of main roster.

Staff
Mario & Sonic at the Olympic Games Tokyo 2020 was developed by Sega in conjunction with Racjin, Mario & Luigi series developer AlphaDream, and several other companies.

Amy

 * "Hello there!"

Luigi

 * "No."

Mario

 * "What?"

Omochao

 * "Alright!"

Tails

 * "Darn..."

Silver

 * "What!?"

References to other games

 * Super Mario Bros.: The Mario, Luigi, Princess Peach, Bowser, Goomba, Koopa Troopa, Hammer Bro, Cheep Cheep, Lakitu, and Toad sprites in the Tokyo 1964 Events are from this game, with the differently-colored Toad sprites being based off of the red sprite.
 * Mario Kart series: During Sport Climbing, when a player falls off the wall, Lakitu picks them up with a fishing rod and places them back on the wall, referencing one of his roles in these games.
 * Super Mario 64: The music for Dream Karate is an arrangement of "Inside the Castle Walls".
 * Donkey Kong 64: Donkey Kong's bio references a line from the DK Rap.
 * Mario Party DS: Diddy Kong's artwork on his trivia card is recycled from this game.
 * New Super Mario Bros.: Bowser Jr.'s artwork is recycled from this game.
 * Mario Kart Wii: Waluigi's artwork on his trivia card is recycled from this game.
 * New Super Mario Bros. Wii: Larry and Wendy's artwork on their trivia cards is recycled from this game.
 * Mario Party 9: Bowser Jr.'s artwork on his trivia card is recycled from this game.
 * Mario Tennis Open: Luigi does his artwork pose from this game on the character selection screen (albeit mirrored).
 * New Super Mario Bros. U: Ludwig's artwork on his trivia card is based on his artwork from this game, albeit without the fire surrounding his wand.
 * Super Mario 3D World: Luigi's artwork on his trivia card is recycled from this game. Some of the voice clips are also recycled from this game.
 * Mario & Sonic at the Sochi 2014 Olympic Winter Games: The character selection screen animations are reused from this game.
 * Mario Kart 8: Some of the voice clips are recycled from this game.
 * Mario Party 10: Mario, Yoshi, and Toadette's artwork on their trivia cards is recycled from this game. Additionally, the pose that Toadette does on the character selection screen is similar to her artwork pose.
 * Mario & Sonic at the Rio 2016 Olympic Games: Donkey Kong's artwork is recycled from this game.
 * Super Mario Maker: The Key and Blooper sprites in some of the Tokyo 1964 minigames use their design from the Super Mario Bros. style in this game.
 * Mario Party: The Top 100: Wario and Rosalina's artwork on their trivia cards is recycled from this game.
 * Super Mario Odyssey: The Mushroom Kingdom serves as the arena for Dream Karate, using its design from this game. The Odyssey can also be seen in the background.
 * Mario Tennis Aces: Mario, Luigi, Peach, Daisy, Wario, Waluigi, and Toadette wear the same sneakers as their tennis outfits in this game.
 * Super Mario Party: Peach and Donkey Kong's artwork on their trivia cards is recycled from this game.
 * Mario Kart Tour: Daisy's artwork on her trivia card is recycled from this game.

Trivia

 * Despite this game having updated victory and losing animations in the events, the animations used in Rugby Sevens are recycled from the previous game.
 * The Boom Booms recycle Bowser's losing animation.
 * In the game's country/region selection, is listed in the "Europe 1" section instead of "Asia", most likely because Israel participates in and is a member of the  instead of the.