Project Overkill Cheats

Turbo:
Pause the game and highlight "Sound Volume." Hold Up and press Triangle, Triangle, Triangle, then release Up; now hold Down, press X, Square, Circle, and release Down. You'll see the word 'cheater' to confirm.

Life Refill:
Pause the game and highlight "Sound Volume." Hold Square and press Circle, X, Triangle, then release Square; now hold Circle and press Square, X, Triangle, and release Circle. You'll see the word 'cheater' to confirm.

Shield:
Pause the game and highlight "Sound Volume." Hold Right and press Circle, Square, Triangle, then release Right; now hold Left and press Square, Circle, X, and release Left. You'll see the word 'cheater' to confirm.

Refill ammo:
Pause the game and highlight "Sound Volume." Hold Circle and press Square, then release Circle; now hold Triangle, and press X. Release Triangle, then hold Circle and press X. Release Circle, then hold X and press Square. Release X. You'll see the word 'cheater' to confirm.

Thanks to Revolution readers Mr. Orbital D. Boy, Steve Jackson, Chris Ray, and X. Calypso!