Hold L1 + R1 and press Left, Square, Circle, Down, Square, X, Square, Circle at the title screen.
Classic Pitfall mini-game
Hold L1 + R1 and press Circle(2), Left, Right, Circle, Square, X, Up, Circle at the title screen. The "Original Pitfall" option will be unlocked at the "New Game/Load Game" screen.
Hyper punch mode
Hold L1 + R1 and press Left, Right, Circle, Up, Circle, Right, Left at the title screen.
Play as Nicole
Hold L + R and press Left, Up, Down, Up, Circle, Up(2) at the title screen.