Mario Kart 7

New additions to Mario Kart 7 include hang-gliding attachments for karts (which introduced aerial sections to race tracks for the first time in the series), the ability to drive in first person, gyro controls, and the ability to customize the vehicles' builds. Additionally, Mario Kart 7 supports both local and online multiplayer through Nintendo Network for up to eight players. The ability to play online was discontinued on April 8, 2024, along with Nintendo Network as a whole. Development of Mario Kart 7 began in early 2010 as a port of Mario Kart Wii. Producer Hideki Konno said that completing the game was an "act of emergency" due to low 3DS sales at that time and because of the very few staff involved in its development. In the end, Retro Studios was involved in the development of the retro tracks (tracks from prior games in the series). 7 received generally positive reviews from critics, who praised its innovations, race tracks, and gyro control option. The game has won several awards and was a commercial success, becoming the best-selling game on the Nintendo 3DS with nearly 19 million copies sold.

Mario Kart 7 retains traditional Mario Kart gameplay in which players race against each other in go-karts across 32 different courses (new and retro). Most of the courses are based on various locations in the Mario series, but two new courses are set on Wuhu Island location from the Wii Fit and Wii Sports Resort games. In addition to traditional button controls, Mario Kart 7 can be played using the Nintendo 3DS gyroscope, in which the action is viewed in first person and the player steers the kart by tilting the entire game system. While most of the race occurs on the top screen of the 3DS hardware, the bottom screen shows an overhead map of the race course. While driving, the players may use power-up items, obtained from running into item boxes located at specific points on the track that are used to hinder the progression of opponents or to help the player in the race. Some of these power-ups include the series staple items such as Koopa Shells, Banana Peels, and Super Mushrooms. Three new items were added: the Fire Flower, which allows the player to shoot up to ten fireballs at other racers; the Super Leaf, which gives the player a tail that allows them to flip over nearby players, collect nearby Coins, and deflect items; and the Lucky Seven, which bestows seven items at once. Coins are also scattered about the tracks; collecting them increases the kart's top speed. Up to ten coins can be collected in each race, but some will be lost if the player comes into contact with hazards or goes out of bounds. Jump actions let players obtain a brief burst of speed when hitting a button prior to driving off ramps, and hang glider attachments sometimes allow for controllable gliding segments as well. In Mario Kart 7, the karts are now fully submersible, and the game adds fully underwater track segments to make use of this feature. The game features sixteen playable characters, including Wiggler, Honey Queen, Lakitu, and Metal Mario, who are new to the series, as well as Mii characters (which are playable in-game) that are saved in the Nintendo 3DS Mii Maker, bringing the total playable character count to seventeen. Like in the previous installments, characters are divided into three different weight classes which impact their driving styles. Mario Kart 7 also introduced the ability to customize vehicles prior to races. Vehicle bodies, tires, and hang gliders can be customized with differing control attributes. Mario Kart 7 features four single-player game modes: Grand Prix, Time Trial, Balloon Battle, and Coin Runners. Some modes feature multiplayer options. In Grand Prix, the player races against seven computer-controlled opponents in one of eight different cups, each featuring four tracks. The player receives points based on their finishing position in each race ranging from one to ten. After all four races, there is an award ceremony and the player may receive a trophy if they place in the top three of the final standings. Players also receive a star rank based on their performance ranging from one to three stars. In Time Trial, the player races alone to finish the course in the fastest time possible with access to a Triple Mushroom, usable at any time during the run. The best time for each track is saved and recorded as a ghost, which the player can compete against in later trials. If the player has SpotPass enabled on their Nintendo 3DS, they can download ghosts from other players and can race against up to seven other ghosts simultaneously. In the Balloon Battle and Coin Runners battle games, the players drive around one of six arenas (three from this game and three from the previous installments) to collect items and attack their opponents to score points within the time limit of two minutes. The player could play online via Nintendo Network until the Network's shutdown in April 2024, participating in races or battles with up to seven other players.

Nintendo EAD began development on Mario Kart 7 in early 2010. The game was initially conceived as a port of Mario Kart Wii for the 3DS. During development, the idea to have hang gliding and submersible karts, which were planned for Mario Kart Wii, were implemented. The ability to customize the player's kart was added in order to make gameplay more strategic and to boost the multiplayer experience. The game was first publicly announced at E3 2010 under the tentative title Mario Kart 3DS and then shown again at E3 2011, where it was announced for a late 2011 release. Producer Hideki Konno described that completing Mario Kart 7 was an "act of emergency" due to the Nintendo 3DS' slower-than-expected sales. Because Nintendogs + Cats was scheduled to be released first, Mario Kart 7 was given lower priority and only eight staff members were assigned to begin work on it. When it was time to focus on the game, producer Hideki Konno realized that there was not enough staff available due to many other titles being developed at the same time, including The Legend of Zelda: Skyward Sword, which had its production extended into 2011. In order to finish the game in time for the 2011 Christmas season, Nintendo consulted with Retro Studios, which had just finished making Donkey Kong Country Returns, to co-develop the game. Retro started work on Mario Kart 7 in December 2010. The team focused on producing the classic racing courses, remakes of courses from the earlier Mario Kart titles, in order to learn both "lessons about the development process [for Mario Kart games]" and "about what makes a good course from a design perspective." One of the lead artists for Mario Kart 7, Masaaki Ishikawa, expressed confusion to whether or not Retro Studios was located in Japan. The team behind Mario Kart 7 expressed nervousness over Retro Studios' part in the development of Mario Kart 7, since the team is used to the games being developed by a standalone team in Japan. When asked about one of Mario Kart 7's new additions—the Kart customization feature, producer Hideki Konno stated that to make Mario Kart 7 more strategic to players, the Kart customization feature was added, which allows the player to choose the frame, kart and glider. Konno's main objective was to make Mario Kart 7 accessible enough for new players so they "can start playing immediately". Konno compared the Kart customization screen to a slot machine. Parts of Mario Kart 7's online community features were originally going to be used in the Nintendo 3DS system software as a whole, including creating online communities and exchanging individual friend codes. Nintendo president Satoru Iwata stated that development time was limited and those features couldn't be added in time, although it was later added in a system firmware update. The game's soundtrack was composed by both Kenta Nagata, who worked on the previous Mario Kart titles Mario Kart 64 and Mario Kart: Double Dash, and by Star Fox 64 3D composer Satomi Terui. Shortly after its release, it was discovered that three race tracks had contained glitches that allowed players to skip over a significant portion of the track, often exploited as a cheat during online play. A patch was released in May 2012 that fixed them.