Mario's Time Machine
Mario's Time Machine is an edutainment title developed by Radical Entertainment that was released for MS-DOS and SNES in 1993; it was later released for the NES on April 23, 1994, alternatively spelled Mario's Time Machine!. It is the successor of Mario is Missing!. It is meant to teach younger players basic world history and is the last Mario Discovery Series game before discontinuation. This game and Hotel Mario are the only games in the Mario series in which Mario as a protagonist has full lines of dialogue. The original PC release was distributed through floppy disks, but there was a Deluxe version provided as a CD-ROM in 1996 which added voice acting and a Library reference file featuring Bowser's mother.
In the year 1993, Bowser uses a time machine, traveling backwards to different points in human history and stealing significant artifacts to place in his personal museum inside his castle. With his collection nearly completed, Bowser gloats that not even Mario can stop him now. Mario realizes that history will change forever if he does nothing, so it's up to Mario to use Bowser's own device against him by returning the artifacts to their proper places in time.
The home console releases add that Bowser plans to destroy his time machine (called a Timulator in console manuals), deliberately planning to irreversibly damage history and send the world back to the Dark Ages. In the NES game, Bowser's Museum has been fully built and already established itself with history's greatest artifacts. Yoshi joins Mario in his quest to stop Bowser's plot, but instead gets captured when he scouts ahead. In addition to fixing the timeline, Mario must also rescue Yoshi from peril.
The central hub of Mario's Time Machine is the museum within Bowser's Castle. The museum is three floors high, and on each floor lies five artifacts, giving Mario a total of fifteen periods of time to travel to. Mario must take an artifact from a pedestal, look at the date and location labeled on it, and then program that information into the time machine and travel to that point in the timeline. Mario surfs the ripples of time, collecting mushrooms and avoiding hazards.
When the player arrives in the time period, he must explore and converse with the various residents that live there. In doing so, the player learns about the artifact, the time period, and the person associated with it. To get more information, the player must receive items that some residents possess and give them to others in order to satisfy their needs. For example, in Vienna one resident will complain about the heat until Mario retrieves a fan and hands it to the person, who will then continue to give information. After the player has talked to everyone, the player fills out a History answer sheet. The answer sheet consists of a two-page biography about the person associated with the artifact and the time period, with blanks replacing several words. The player must use the information he received to correctly fill in the blanks. If the player fills in the wrong answer more than twice, the player is forced back into the present. If he succeeds, Mario can return the artifact to its owner and return back to 1993. After all the artifacts of a floor have been returned, Mario moves upward to the next floor.
A timer and a hidden Checklist are used throughout the game. How long the player spends in each time period and the order in which he returns each artifact will total up to one of three different endings. If the player spends too much time returning all the artifacts or returns even one artifact in the wrong order, Bowser escapes to "Paradise" using the time machine; then the player must start over from the beginning, or use a password to go back to a previous point. However, if they meet the two objective conditions, the time machine overloads, self-destructs and sends Bowser to the Jurassic period where he gets stepped-on by a Tyrannosaurus Rex.
Being a port of the PC release, the SNES version has a few changes to the original game. There is less content overall, so Mario travels to fewer time periods, and there are some graphical changes such as the design of the time machine. During the sequence on time's waves, Mario can move in all directions rather than just forward due to the use of Mode 7 on the water, and he must go in a whirlpool after collecting ten mushrooms.
Unlike Mario Is Missing!, the NES release is virtually a different game with little resemblance to its previous incarnations, traveling to very different time periods and restoring entirely different objects. Bowser's Museum is largely a hall with seven doors ending with Bowser's chamber. Behind each door is a Mario Bros.-style mini-game involving Koopa Troopas with a unique item that can be acquired if Mario defeats all of them. The Timulator is in the bottom center of each room, and it is a Warp Pipe with a transparent box. Inside the Timulator, Mario can select pre-determined time periods rather than input them manually, although the location is not disclosed. Once warped across time and space, Mario will arrive at a short platforming land with enemies and occasionally indigenous inhabitants of the time period. There are also Message Blocks which describe the location. Mario must take the item acquired in the mini-game and return it to the appropriate spot - if is in the incorrect place it will return to the clutches of the Koopas, but if Mario is right then he will complete that area. There are two artifacts in each door, so Mario must enter a door at least twice before he can close that section of the museum. After all the doors of the museum are cleared, the deeper part of the castle is available after Mario passes a random History Test about what he's learned. After beating Bowser, a key will be released and Mario will free Yoshi from his cage. In the end, Mario and Yoshi pose next to a saddened, crying Bowser.
 Time periods
The time periods that Mario visits in each version varies. Here is a chart of the location and artifact for the PC, SNES and NES versions in chronological order.
Since its release, Mario's Time Machine has received negative reception. It holds an aggregate score of 60.25% on Game Rankings based on two reviews. Nintendo Power gave it a 2.65 out of five, while Electronic Gaming Monthly gave it a slightly better rating of 6.75 out of 10. GameSpy's Brian Altano and Brian Miggels criticized its ending (considered to be one of the worst video game endings ever) for its depiction of Bowser crying, while Mike Drucker, also a GameSpy editor, called it "half-assed." Gamesradar commented that fans of the game would be fans of Night at the Museum: Battle of the Smithsonian, to which Gamesradar also gave a negative review. Later, they mentioned that Mario's Time Machine was unpopular, commenting that "five, maybe six people played the NES version of Mario’s Time Machine". ABC Good Game called it "awful," and they considered it to be "way too complicated for any school-aged youngster to understand." In the book Video Games: A Guide for Savvy Parents, author David Sheff praised the educational elements but criticized the gameplay. Andy Slaven, author of the book Video Game Bible, 1985-2002, accused the game of ripping off Where in Time is Carmen Sandiego? He admitted that the game was not bad in and of itself, but he stated that it was a poor educational game.
 References to other games