Zombies come out of checkpoint caskets. They can be steered left or right by by pressing the left or right arrow keys. They can be slowed down by pressing the down arrow key or sped up by pressing the up arrow key. Any hazards or enemies will kill the zombie and make another zombie come out of the checkpoint casket that was last touched. When a zombie gets killed it's head will come off it's body and both will fall off the screen.
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The zombies were last seen coming up out of the ground and beginning to take over the world.