While playing the game, press Up, Square(2), Down, Left, Square(2), Right. If you entered the code correctly, a message will appear. The brass knuckles, knife, Molotov cocktails, 9mm handgun, shotgun, Tec-9, AK-47, flamethrower, and sniper rifle will be unlocked. To get infinite ammunition for this or the other weapons tiers, repeatedly enable the code until no ammunition number appears beneath the gun pictures. Note: Enabling this code will cause your street creds to substantially drop in points. You can check your creds in the stats menu at the pause screen.