Army Men: 3D

Invincibility
Pause the game and quickly press Square, Circle, L1, L1 + L2. Then, Sarge will be invincible during the current level. Or, pause the game and press R1, L1, R1 + R2 within two seconds.

All weapons
Pause the game and quickly press Square, Circle, R1, L1, R1 + R2. Then, Sarge will have access to all the weapons during the current level. Or, pause the game and press L1, L1 + L2 within two seconds.

Open All War Zones
Go in Options, Difficulty, and hold Triangle, Square, Circle, and press L1+L2.

First person view
While playing a game, hold Start + Circle + Square. The game will pause. Press Start to resume the game in the first person view.

Hints
Clear Mine Fields Quickly
When entering a mine field, select your minesweeper. Walk forward a few paces and then hold in the roll button and roll left/right to clear mines. This will save a considerable amount of time.

More Damage in Multiplayer
When using the flamethrower in two player mode, tap the X button instead of holding it. The flamethrower will then do more damage.

Run Faster in Multi-Player Mode
Hold Square + Triangle to chase your opponent quicker.

Secret Artifact
In level two, kill the Blue Spy and pick up the information he leaves behind. When you're ordered to evacuate the area, now ignore your orders and go to the Tan Post. Kill the guys their and cycle through your weapons until you see the info as your weapon. Press SELECT and read it.

Secret Key
If you enter the two player level "Clean Up This Mess!," and go into the closet (located in the North East direction, you will find a key located between the books. Once you have the key, look at your radar. You will see 2 doors, 1 is the closet, the other is where you use the key. Take the key there. When you are close enough, you will automatically use it.

Game Shark Codes
Infinite Health            800432A0 2400
Infinite Ammo              80057FD2 2400
Infinite Flamethrower Fuel 80058E3E 2400