Shoot all of Amsel's henchmen, including their attack dog, without reloading. (Solo only)
In 'Black Cats', blast out all of the spot lights in the Japanese cargo convoy. (Solo only)
Throw a Six and a Half
On Hardened or Veteran difficulty, complete a level without dying. (Solo only)
It's a Trap!
Kill at least one zombie with three different traps in a single round. (Map Pack 2 only)
Acquire Waffle Weapons!
Obtain the Ray Gun, DG-2, and the Monkey Bomb at the same time in a game. (Map Pack 3 only)