The 3DS version of Mario & Sonic at the London 2012 Olympic Games has some key differences from the Wii version. While it shares many events, it has more. It also features an exclusive Story Mode. The protagonists from the Mario and Sonic series team up to defeat Bowser and Dr. Eggman, who, along with their underlings, have taken over London. There are different parts to the story, depending on the character played. The player must win events against the antagonists. Playable characters consist of all 20 playable characters from the previous installment’s Nintendo DS version, and are split into five groups of four.