All Weapons
Pause the game and press R1+Square, Triangle, Circle, X.
Big Head Mode
Pause the game and press L1+L2+R2+Down.
Hidden Boss
To fight a hidden boss, enter the password: Circle, Square, Square, X, Circle, X, X, Circle.
Increase Clean Points
Pause the game and press L1+L2+Circle+Square.
Invincibility
Pause the game and press Circle, Square, Left, Right+R1+R2
Special Mode
Pause the game and press R1+R2+Triangle+Circle.