Unlockables:

All Characters - At the menu screen quickly press Right, Down, Down-Right, Down, Down-Left, Left, Triangle. You should hear a ''whack'' sound and the Game Start'' letters should turn red.

Extra Mode - At the menu screen hold left for several seconds, then quickly press Right, Circle, Triangle. You should hear a ''whack'' sound and the option letters should turn red.

Versus Mode - At the main menu, press Down, Circle, Right, Square, Up, X, Left, Triangle.

Hope you enjoy!