Invincibility:
Press Start to pause game play, then quickly press Square, Circle,
L1, then hold L1 and press L2. Sarge will be invincible
during the current level.
All weapons:
Press Start to pause game play, then quickly press Square, Circle,
R1, R2, then hold R1 and press R2. Sarge will have
access to all the weapons and unlimited ammunition during the current level.
Level select:
Quickly press Square, Circle, R1, L1, L1
+ R1 at the main menu. To unlock all war zones, hold Triangle + Square
+ Circle and press L1 + L2 at the difficulty option screen.
More tanks:
Quickly press Square, X(2), R1, R2 at the main
menu.
Run faster in multi-player mode:
Hold Square + Triangle to chase your opponent quicker.