Pause the game and enter the following:

Big feet:
Right, Right, Right, Left, Right, Left, Right, Left, Left, Left.

Big gun:
Square, Square, Square, Square, Circle, Circle.

Skeleton:
Left, Left, Left, Right, Left, Right, Left, Right, Right, Right.

Explosive crossbow:
Left, Right, Right, Left, Square, Circle, L2, R2, Square, Circle, Left, Right.

Explosive sniper:
L2, R2, Right, Right, Left, Left, Right, Right, R2, L2, Square, Circle.

Missile crossbow:
Right, Right, Left, Left, L2, L2, R2, R2, Circle, Circle, Square, Square.

Missile sniper:
Square, Left, Right, L2, R2, Right, Square, R2, R2, L2, Left, Left.

Half damage:
Square, Square, Circle, Circle, Left, Left, Right, Right, Circle, Circle, Square, Square.

No bullet damage:
Left, Right, Right, Left, Square, Circle, Circle, Square.

One hit kills:
Circle, Left, Right, Right, Left, Circle, L2, R2, Circle, Square, Square.

Unlimited bullets:
Square, Circle, Square, Circle, Square, Circle, Square, Circle, Left, Circle, Square, Circle, Square, Circle, Square, Circle, Square.

Unlimited health:
Left, Right, Right, Left, Left, Right, Right, Left, Left, Right, Right, Left, Square, Square.

Unlimited Spy Cam:
Left, Left, Right, Right, R2, R2, L2, L2, Square, Square, Circle, Circle.

Unlimited TOC:
Circle, Circle, Square, Square, Left, Right, Right, Left, L2, R2, L2.

Level skip:
L2, Square, L2, Circle, L2, Left, L2, Right, L2, R2, R2, Square, R2, Circle, R2, Left, R2, Right, Square.

Level completion codes must be entered within the corresponding level to work.

Bank level completed:
R2, L2, Square, Circle, Left, R2, Left, Left, Square, Circle, Square.

Carmen level completed:
R2, L2, Right, Left, Left, L2, R2, Square, Square, Square, R2.

Forsythe level completed:
L2, L2, Right, Right, Right, L2, R2, Square, R2, Square, R2.

Installation K level completed:
R2, L2, Square, Square, Left, L2, L2, Square, Square, L1, Square.

La Casa level completed:
R2, L2, Right, Left, Left, L2, R2, Square, Square, Square, R2.

Magyar level completed:
R2, Circle, Circle, Left, Left, L2, R2, Right, Square, Right, Right.

Mod level completed:
R2, L2, Right, R2, Left, Circle, R2, Circle, Right, Right, Left.

Museum level completed:
L2, L2, Right, Right, Right, L2, R2, Square, R2, Square, R2.

Reliance level completed:
R2, L2, Right, Left, R2, L2, Right, Square, Circle, Square, Circle.

Silo level completed:
R2, L2, Right, Left, Left, L2, Circle, R2, Square, Square, Square.

Training level completed:
Left, Right, Right, Left, Circle, Square, R2, L2, Circle, Circle, Square.