Invincibility
     Pause gameplay and press L1, L1, L2, L2, R1, R1, R2, R2.

Unlimited Ammo
     Pause gameplay and press L1, L2, R1, R2, Triangle, Circle, X, Square.

All Weapons and Full Ammo
     Pause gameplay and press L1, L2, R1, R2, Triangle, Circle, X, Circle.

Level Select
     Play up to Subway A1. Return to the Main Menu and press Up, Down,
Left, Right, Up, Left, Down, Circle.

8 Pain Killers
     Pause gameplay and press L1, L2, R2, R1, Triangle, Circle, X, Square.