Mario Tennis Aces

Mario Tennis Aces is a sports game in the Mario Tennis series for Nintendo Switch, initially released on June 22, 2018. It is the eighth installment in the series and is the first Mario Tennis series game since Mario Tennis: Power Tour on the Game Boy Advance to feature a Story Mode.

Gameplay
The base gameplay appears similar to that of Mario Tennis: Ultra Smash, featuring different types of shots. Characters have an energy gauge that can be used to perform Zone Shots, Zone Speed, or Special Shots. The energy gauge can be increased by simple rallies or by performing Trick Shots, which require proper timing to hit the ball back. Zone Shots can be performed upon reaching a rotating star icon on the ground, and allow the player to aim their shot anywhere on the court using motion controls. The longer they take to aim, the more energy it depletes. Zone Speed allows the player to slow down time to allow them to reach a far-off shot in time. Special Shots are performed like Zone Shots, but require a full energy gauge. Zone Shots and Special Shots are able to damage rackets. Rackets can withstand three Zone Shots or one Special Shot before breaking, and after being broken they are replaced with a new one, forcing the player to retire when they no longer have any usable racket. With proper stroke timing, these shots can be blocked, increasing the character's energy gauge and protecting their racket from damage. In doubles, each pair shares one energy gauge, and if a player's racket breaks during a rally, that player's team immediately loses the point. Also in doubles, each player has their own racket counter. When playing in doubles, the match will end if just one player loses all of their rackets (no matter how many rackets that player's teammate has remaining) and that player's team immediately loses. Exclusive to doubles, the result screen also shows X marks in the sections where a player's racket took damage, and the X marks are colored as appropriate to show which opponent did the damage to that player's racket. Unlike Mario Tennis: Ultra Smash, there is a left-handed option for characters.

Other than the base style of gameplay, the game also includes a "simple rules" mode which excludes the new types of shots, as well as "Swing Mode", which allows the player to use motion controls to swing their racket, similarly to . Unlike Mario Tennis: Ultra Smash, the game features a traditional Tournament mode where the player can challenge computer opponents in an 8-player bracket. Online multiplayer is also supported for up to four players (friends or other players) as well as for online tournaments. Participating in these can provide the player with participation prizes, including special in-game outfits or additional playable characters.

Exclusively in Swing Mode, players can challenge a decision that the ball was shot out of the court.

Adventure Mode
The game also features a story mode set on an island, which includes various challenges for the player to complete, such as missions and boss battles. The story focuses on Mario (partnered with Toad) as he tries to rescue those that have been possessed by a dark force, whose energy is imbued in a special tennis racket called Lucien. The possessed characters take on a mummy-like appearance with glowing eyes, and their souls are taken by the dark force. To rescue them, Mario has to go around the island and complete challenges given to him by various Mario franchise enemies, like Boos and Petey Piranha, in his attempt to locate the five Power Stones that power the racket before Lucien does. Wario and Waluigi heard the myths of this powerful racket and wanted it for themselves, becoming corrupted by its power. Aster, who resides in the Temple of Bask, tells Mario of his objective and teaches him the skills needed to restore peace to the island. Along the way he can obtain different rackets that have different attributes, as well as level up his own stats such as running speed. Should the player's rackets all break, they will receive a game over.

The level selection appears to be based on that of the New Super Mario Bros. series, with red circles indicating an unfinished level and blue circles indicating a completed level, with the name of the level being shown when Mario stands on one.

Bask Ruins

 * Bask Ruins: A Bone to Pick
 * Temple of Bask: An Ancient Trial

Piranha Plant Forest

 * Piranha Plant Forest: Pipe Gripe
 * Forest Practice Court: Rally Challenge (Beginner)
 * Piranha Plant Habitat: Rapid Fire
 * Forest Edge: Sure Shot Challenge (Beginner)
 * Ancient Altar: Forest Monster
 * Bay Ferry: Battle Boat

Mirage Mansion

 * Mirage Mansion: Malicious Mirrors
 * Mansion Practice Court: Panel Challenge (Beginner)
 * Reflection Room: The Great Mirror Mystery
 * Detour: Rally Challenge (Intermediate)
 * Royal Chamber: All Hail the Mirror Queen

Snowfall Mountain

 * Snowfall Mountain Station: Snowball Fight
 * Snowfall Mountain: One versus...One?
 * Station Square: Sure Shot Challenge (Intermediate)
 * Snowfall Mountainside: Panel Challenge (Intermediate)
 * Snowfall Mountain Summit: Snow Ogre Showdown

Savage Sea

 * Savage Sea Coast: The Sort-Of Sea Monster
 * Savage Sea Bay: The Sea Monster Attacks!
 * Savage Sea: Rally Challenge (Advanced)

Inferno Island

 * Inferno Island: Mechakoopa Crisis
 * Castle Bridge: Sure Shot Challenge (Advanced)
 * Castle Practice Court: Panel Challenge (Advanced)
 * Castle Gates: Defeat Bowser's Minions!
 * Bowser's Castle: Battle the Treasure Guardian!

Marina Stadium

 * Marina Stadium: Lucien Cup Finals

Temple of Bask Shrine

 * Temple of Bask Shrine: The Final Battle!

Playable
Mario Tennis Aces differs from prior entries in the series in that there are no traditionally unlockable characters. Rather, only the default characters and Koopa Troopa are currently playable, with more characters set to be added in monthly online tournaments.

Adventure Mode opponents
Unlike their playable versions, they cannot perform Trick Shots and Special Shots. Wario, Waluigi, and Luigi can perform Trick Shots and Special Shots.
 * Dry Bones (tutorial) - opponent in A Bone to Pick.
 * Donkey Kong - opponent in Pipe Gripe.
 * Toad - opponent in Rally Challenge (Beginner).
 * Spike - opponent in Sure Shot Challenge (Beginner).
 * Koopa Troopa - opponent in Battle Boat.
 * Boo - opponent in Malicious Mirrors and Rally Challenge (Intermediate).
 * Shy Guy - opponent in One versus...One? and Sure Shot Challenge (Intermediate).
 * Blooper - opponent in The Sort-Of Sea Monster.
 * Kamek - opponent in Rally Challenge (Advanced).
 * Boom Boom - opponent in Mechakoopa Crisis.
 * Chain Chomp - opponent in Sure Shot Challenge (Advanced).
 * Wario and Waluigi - opponents in Lucien Cup Finals.
 * Luigi - opponent in Lucien Cup Finals.

Bosses

 * Petey Piranha
 * Madame Mirage
 * Snow Ogre
 * Gooper Blooper
 * Bowser Statue
 * Bowcien

Non-playable characters

 * Piranha Plants
 * Lakitus
 * Biddybuds
 * Yoshis
 * Little Birds
 * Rabbits
 * Fire Piranha Plants
 * Munchers
 * Piranha Creepers
 * Ant Troopers
 * Conkdors
 * Kleptos
 * Peepas
 * Bob-ombs
 * Spinies
 * Mechakoopas
 * Monty Mole
 * Lumas
 * Fishin' Lakitu
 * Parabones
 * Bullet Bills
 * Whomp
 * Aster
 * King Bask
 * Lucien

Audience members

 * Toads
 * Shy Guys
 * Koopa Troopas
 * Koopa Paratroopas
 * Hammer Bros
 * Sledge Bros
 * Goombas
 * Paragoombas
 * Penguins
 * Stone Spikes
 * Fire Bros
 * Boomerang Bros

Possible future playable characters
In a reported datamine of the demo, Boom Boom, Shy Guy, Kamek, Dry Bones, and Dry Bowser were listed as playable characters. Additionally, the latter’s emblem can be seen on a few of the in-game advertisments.

Courts
Like in Mario Power Tennis, some courts contain hazards that can be toggled on or off.
 * Marina Stadium (Hard, Clay, Grass, Night)
 * Bask Ruins (a court set in desert ruins)
 * Piranha Plant Forest (a court set in a forest - Piranha Plants can eat the ball to change its direction)
 * Mirage Mansion (a court set in a haunted house)
 * Snowfall Mountain (a court set in a snowy plaza)
 * Savage Sea (a court set on an airship flying over a sea, apparently themed after New Super Mario Bros. U)
 * Inferno Island (a court with hexagonal tiles, featuring Mechakoopas and Bob-ombs)

Demo and pre-launch online tournament
Prior to the game's release date, a free demo was released on the Nintendo eShop on May 24, 2018. This demo included a pre-launch online tournament, as well as the ability to practice with CPU players. The tournament allowed players to play as Mario, Peach, Yoshi, and Bowser, with Waluigi, Toad, Spike, Rosalina, and Chain Chomp becoming available as players earned points, for a total of nine playable characters. All tournament participants could receive an alternate costume for Mario that dresses him in his usual clothes (effectively making him appear identical to his appearance in Mario Tennis: Ultra Smash), usable in the full game.

Reception
Mario Tennis Aces received somewhat positive reviews from critics. Praise was directed at the visuals and many welcomed new additions of gameplay, but minor criticism was directed at customization and the story mode, with some considering the latter not being rewarding or satisfying enough. The Swing Mode also received mixed reception, with points of contention directed at its responsiveness. The game currently holds a score of 78% on Metacritic based on 32 reviews, and a score of 76.86% on GameRankings based on 14 reviews.

Tristan Ogilvie gave the game a score of 7.5/10, praising the visuals, the court gimmicks, and the multiplayer mode, but criticized the story mode (considering it bare-bones, with nothing making it a fresh and satisfying experience), and also criticized the way local multiplayer works, stating "The biggest problem with Mario Tennis Aces[s] Adventure mode is how poorly it incentivises you to keep playing. I had completed all 27 of its levels and unlocked all of its courts and rackets by the time I was on level 34, which was around a half a dozen hours of game time. Out of curiosity, I replayed a number of the challenges and boss fights several more times over to grind my way up to level 55, but was rewarded with absolutely nothing aside from incremental boosts to Mario's stats, thus making the existing challenges even easier. With no New Game+ or more challenging versions of its levels to unlock, or even the option of playing through it with a different character, Mario Tennis Aces[s] Adventure mode becomes increasingly simple and repetitive the more time you put into it." In a more positive review, Mike Diver of Nintendo Life gave the game an 8/10, praising what he believed to be vast improvements over its Wii U predecessor Mario Tennis: Ultra Smash, stating "Where [Mario Tennis:] Ultra Smash's extras were a pure Monkey Island's worth of living without that particular piece of junk – here's your context, kids – [Mario Tennis] Aces stuffs its kit bag with activities until the zip's positively pinging off across the locker room like a smartly volleyed can of energy drink. Not everything is evenly fleshed out, but whatever your preferential way to play, there's plenty to get stuck into, both solo and with pals." In a slightly more positive review, Justin Clark of GameSpot gave the game an 8/10, praising the game's new playing mechanics over past games as well as the story mode's incentive to teach players of the new mechanics, but had mixed to somewhat positive feelings about the story mode, stating "The story itself is ridiculous, but ridiculous in that very specific, quirky way Nintendo has been getting away with for decades. During the Mushroom Kingdom's annual tennis tournament, an evil tennis racket--yes, really--named Lucien takes possession of Luigi and flies off to find five Power Stones that will help him take over the world."

Pre-release and unused content
The Special Chance Shot markers from Mario Tennis: Ultra Smash, needed to perform the Ultra Smash, were featured in the announcement trailer. The animation Mario performed there was also the same one used for those kinds of shots. In the final game, however, those Chance Shot markers were rather replaced with a rotating star marker, similar to the ones featured in Mario Tennis and Mario Power Tennis, and Zone Shots replaced Ultra Smashes, while retaining their character animations at least in the case of Mario.

The HUD icons for Mario, Luigi, Wario, and Waluigi originally used their traditional outfit.

Originally, Daisy's final entrance pose showcased her with her mouth closed via a Nintendo Treehouse Log post. In the final game, her mouth is open.

References to other games

 * Super Mario Bros.: A cutscene after the credits shows Mario drawing his cap on the camera lens with a marker pen. The rubbing sounds are the first few notes of the overworld theme.
 * Super Mario Bros. 3: Boom Boom's running animation is flailing his arms while facing the opponent, mirroring his sprite animation from this game.
 * Mario's Tennis: This is the first time in the Mario Tennis series since this game that Mario and Luigi wear short-sleeved T-shirts and shorts and athletic shoes instead of their standard overalls. However, here they wear visor versions of their signature caps while in Mario's Tennis they wear their usual caps.
 * Super Mario 64 / Super Mario 64 DS: The design of Snow Ogre highly resembles that of Eyerok. Also, the music that plays while battling Bowcien is a remix of Bowser's battle theme and the Bowser levels from this game.
 * Super Mario Sunshine: The sounds that Piranha Plants make are reused from this game.
 * Mario Power Tennis: The sound Chain Chomp makes is reused from this game. Many characters' voice clips from this game are reused for their Special Shot animation.
 * Mario Party 6: Mario's artwork from this game is reused on one of the large banners.
 * Mario Party 8: Chain Chomp's artwork on the character select screen is from this game.
 * Mario Party DS: Wario's artwork from this game is reused on one of the smaller banners.
 * New Super Mario Bros. Wii: Boo’s artwork from this game is reused on one of the smaller banners.
 * Mario Party 9: Koopa Troopa's artwork on the character select screen is from this game.
 * New Super Mario Bros. U: The Koopalings' airships from this game appear flying in the background of Savage Sea. The large claw arm Bowser Jr. uses for his Special Shot also returns from this game.
 * Super Mario 3D World: Several enemies from this title appear in the background of the courts, such as Piranha Creepers and Conkdors. Rabbits also appear and retain their design from this game.
 * Mario Golf: World Tour: Several of Rosalina's voice clips, provided by her former voice actress (Kerri Kane) are taken from this game.
 * Mario Party 10: The artwork on the character select screen for Rosalina, Spike and Toadette are from this game.
 * Puzzle & Dragons: Super Mario Bros. Edition: Artwork of Luigi and Yoshi from this game are reused on one of the smaller banners.
 * Mario Tennis: Ultra Smash: Marina Stadium bears a striking resemblance to the stadium found in this game. Character models, animations, and voice clips are reused from this game. Yoshi's artwork is also recycled from this game.
 * Mario Party: Star Rush: The artwork on the character select screen for Luigi, Waluigi, Daisy, and Blooper, as well as the artwork for King Boo (used for Boo), are from this game.
 * Mario Sports Superstars: Character shield emblems are inspired and derived off this game.
 * Mario Party: The Top 100: Wario's artwork on the character select screen is from this game.