Sonic Generations (U) (ソニックジェネレーションズ) is a 3D action-adventure platformer game developed by Sonic Team and published by Sega for the Nintendo 3DS. The game follows Sonic the Hedgehog, who is sent back in time to save the world from the evil Dr. Eggman. Players control both classic and modern versions of Sonic in order to complete levels, collect rings, and defeat enemies. The game features a variety of levels, including classic side-scrolling levels, 3D platforming levels, and bonus levels. Players can unlock additional levels, characters, and power-ups by collecting rings. The game also features an online multiplayer mode, where players can compete against each other in races and battles. Sonic Generations (U) is an exciting and fast-paced game that is sure to please fans of the Sonic franchise.