
Push the buttons!
RB, RB, RB, B, B, B, X, at the character select screen, then select any character
Play as Tofu Boy (pc only):
type in "petaphile" in at the character select screen, then select any character.
Special ability: No matter what time it takes with him to complete a level, you always get A+. But he moves extremely slowly and has the lowest jump height in the game.
Play as Tim:
Type "outtatime" in at the character select screen, then select any character.
Special ability: Pressing shift will move Tim by his previous moves, essentially a "reverse"
Play as a Goo Ball:
Type "ballgoo" in at the characters select screen, then select any character.
Special ability: Goo has a slower jump height and speed, but pressing shift while on a wall slows Goo Ball's descent drastically.
By the way, you need to type these cheats fast!