This achievement is a lot easier than it looks on paper, the easiest method is using the Dead Ops Arcade Solo First Person Advanced Start mode, this mode allows you to get a game over and try again from a checkpoint, this is massively beneficial as a full playthrough takes easily over an hour, the first person mode also allows you to take multiple hits instead of dying instantly on contact with a zombie. There’s multiple fates that you can acquire in the Room Of Fates, but the Fate of Firepower is by far the best one as it gives your character a permanent Death Machine that will allow you to kill everything, including the final boss much more effectively.