Left 4 Dead, a new innovative multiplayer shooter released two months ago, is taking fans of multiplayer shooter games by storm. It elevates cooperative gameplay by several levels by pitting four players against an army of running, shrieking undead. I haven't researched this one fully but from what I've heard, there's no story; just a run from Point A to a rescue point. The game relies solely in its cathartic value of killing (again) hordes of mindless individuals hungry for your blood and viscera.
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And oh, the undead spawn randomly so no level plays the same way twice. Also, there are several types of undead in the game, the most interesting of which is the witch (rhyme not intended :P). Judging from the intro movie, it's not as perceptive as the other zombies but multiplayer shooter fans will be quick to learn to turn off their flashlights if they want to avoid being detected by the agile and dangerous witch.