BFG (M249 SAW) in City Streets level:
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.
Silver weapons:
Successfully complete the game under the normal or hard difficulty settings. All guns will now be silver and have unlimited ammunition.
Black Ops difficulty setting:
Successfully complete the game on the hard difficulty setting.
M16A2:
Successfully complete the game under the Black Ops difficulty setting. You will now have the M16A2 (M16 with grenade launcher attachment) on every level.
(52 votes)
Source: 
(51 votes)
