The dead shall inherit the Earth. Again, actually, if Valve have anything to say about it. Despite some valiant former attempts at zombie genocide, there are still plenty of the walking dead to shoot in America's southern states. In a perfect world you would just be able to hide in a closet until the bother dies down, but that apparently wouldn't make for a very good first-person shooter. This is why play.tm is not in charge of Left 4 Dead 2.