Excerpt from [wikipedia]:
“Mario Kart 7 carries on traditional Mario Kart gameplay in which players race against each other in go-karts across a variety of themed tracks. While driving the players are able to obtain power-up items that are used to hinder the progression of opponents, which include the series staple items Koopa Shells, Banana Peels, and Super Mushrooms. Mario Kart 7 also features three items new to the Mario Kart series: the Fire Flower, the Super Leaf, and Lucky 7, which bestows seven items at once. In addition to traditional 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 simply by turning the entire game system.
Mario Kart 7 is particularly notable for sporting features unseen in previous Mario Kart installments. Players are able to customize their vehicles, choosing from various frames which range in weight, a selection of tires which affect a kart’s handling on certain surfaces, and a choice of retractable hanggliders, which allow players to glide through the air. Hang gliding may allow players to skip over parts of the track or locate new routes and shortcuts that are otherwise unaccessible. In past games, driving the kart into a body of water was considered going out of bounds and was penalized by delaying the player for several seconds. In Mario Kart 7, the karts are fully submersible and the tracks feature segments that are completely underwater.”