Modern Warfare 3's Spec Ops Survival mode has you and a friend fending off waves of enemies. Who are they? What do they want? Why have they strapped bombs to dogs and trained them to charge this strategically unimportant spawn point? These questions will never be answered. The important thing is that you can spend points gained for killing these dogs to buy better weapons to kill more dogs. You'll also face men in black pjamas, standard soldier types and hulking bullet-sponges called juggernauts. See more of the survival mode in action in the clips from its live demo on US TV .