Infinite health

Enter the options screen and choose the "Credits" selection. Then, press L1, Triangle, Up, Down, Circle(2), Triangle, Square, Right, Square.

Maximum ammunition

Enter the options screen and choose the "Credits" selection. Then, press L1, Triangle, Up, Down, Circle(2), Triangle, Square, Left, Triangle.

Instant death with all firearms

Enter the options screen and choose the "Credits" selection. Then, press L1, Triangle, Up, Down, Circle(2), Triangle, Square, Down, R1.

Instant puzzle solution

Enter the options screen and choose the "Credits" selection. Then, press L1, Triangle, Up, Down, Circle(2), Down(3), Up.

Expert mode

Enter the options screen and choose the "Credits" selection. Then, press Down(3), Triangle, Down(3), Square, Left, Right for tougher enemies.