During gameplay pause the game and hold L1 and enter the following codes to unlock the corresponding effect. These codes can also be entered at the Main menu.

Unlock Level Select:
Press Circle, X, Circle, Square, Square, Triangle, X, X.

Unlock Invincibility:
Press Square, X, Triangle, Triangle, X, Square, Circle, Circle.

Unlock ALL Doors:
Press Triangle, Square, Square, Triangle, X, Circle, Square, Triangle.

Unlock ALL Maps:
Press X, Circle, Square, Triangle, Triangle, Square, Circle, X.

Unlock Full Health for Entire Team:
Press Triangle, Triangle, X, Circle, Circle, X, Square, Square.