Black

Enter 5SQQ-5THA-ZFFV-7XEV as your profile name. After selecting "Done", you will be able to re-enter an actual profile name. This is how you know the code was accepted. When you begin the first level, you will have the BFG weapon.

Successfully complete the game on the hard difficulty setting.

You can't prime grenades in Black, and enemies will often run away from grenades the moment they see them. To make your grenades explode instantly, shoot 'em with your guns. You don't even have to be totally accurate.

Successfully complete the game under the Black Ops difficulty setting. You will now have the M16A2 (M16 with grenade launcher attachment) on every level.

When you need to reload, hit the reload button and quickly press the melee attack button to cancel the reload. Immediately press the reload button again to reload your weapon without the obstructive distance blur.

Successfully complete the game under the normal or hard difficulty settings. All guns will now be silver and have unlimited ammunition.