The premise of Killing Floor is thinner than thin. Some biotech company has been busy conducting genetic experiments for military purposes. These predictably go wrong, and now mutated, deadly, and very hostile Specimens are running all around London slaughtering and devouring people. You are a member of a British Special Forces team sent in to deal with this threat by using your advanced medical training to test the effects of bullets - on them. All right, maybe not so much that last part.