the game follows sonic and his friends as they try to stop dr. eggman from taking over south island. four characters are playable in the game: sonic, tails, knuckles, and amy. each character has their own special ability: sonic can defeat enemies with a shield attack, tails can fly, knuckles can glide and climb on walls, and amy can attack enemies with her hammer (the other characters defeat enemies by jumping on them). the game marks the first appearance of amy in a 2d "sonic" game.