Go to the main menu and press Square, Square, Square, Square, Circle, Circle, Circle, Circle, Triangle, Triangle, Triangle, Triangle, Square, Circle, Triangle.
Master Cheat (Unlock Everything)
Go to the main menu and press quickly Up, Down, Up, Down, Up, Down, Up, Down, Up, Down, Left, Right, Left, Right, Left, Right, Left, Right, Left, Right. A message will indicate correct code entry.