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.