Kill the zombies. Collect their heads. Don't get eaten. Sound simple enough? Oh yes, and progress through the level within a decent span of time. All of this you will do while progressing through an underground labyrinth that is the zombie's hide out. Be very careful, because they may come at you straight on, but they can also be hiding both above and below you. And here's to guessing that an aerial zombie attack would not be welcomed by any living human being. Use the keyboard to maneuver, and your mouse to shoot zombies, before you become their sunday brunch.