Army Men 3D

All Weapons - Pause gameplay and press Square, Circle, R1, L1, R1 + R2.
Invincible Sarge - Pause gameplay and press Square, Circle, L1, L1 + L2.
Level Select - At the Main Menu, press Square, Circle, R1, L1, hold L1 + R1 and press R2.
More Tanks - At the Main Menu, quickly press Square, X, X, R1, R2.
Open All War Zones - In Options, Difficulty, hold Triangle + Square + Circle and press L1 + L2.