Although I'm a huge fan of Versus Mode, the $5 add-on for Resident Evil 5, it is slightly ridiculous as a multiplayer shooter. For better and worse, Call of Duty 4 this ain't. The above awesome interpretation, cribbed from the comments section here, isn't far from the truth. However, to get the full picture, imagine the above with criss-crossing laser beams and about a dozen zombies shuffling around.

(Thanks Neuromancer!)