During a game, enter any of the following codes to unlock the corresponding weapon. If you entered the code correctly, you'll automatically be armed with the unlocked weapon.

AK47:Press Left, Right, Down, R2, triangle.
Flame Thrower: Press Left, Right, Down, R1, circle.
Grenade:Press Left, Right, Down, R2, square.
Grenade Launcher:Press Left, Right, Down, R1, Square.
M16:Press Left, Right, Down, R2, circle.
Minigun:Press Left, Right, Down, R1, triangle.
Molotov Cocktail:Press Left, Right, Down, R2, X.
Pepper Spray:Press Left, Right, Down, L1, square.
Pistol:Press Left, Right, Down, L1, square.
Rocket Launcher:Press Left, Right, Down, R1, X.
Shotgun:Press Left, Right, Down, L2, square.
Tazer:Press Left, Right, Down, L1, circle.
Tear Gas:Press Left, Right, Down, L1, X.