The game works like thisAt the start of each round, players can either choose to join the human team or volunteer to be the first zombie. If no one volunteers the game will pick one human randomly, and the game begins! The starter zombie's goal is to kill the humans while the human goal is to stay alive as long as possible, complete objectives, or even wipe out all the zombies. The catch is that when a human dies he will simply join the ranks of the undead, now ready to finish off his old living teammates. The humans can't tell by the player list who is alive and who is undead.
Eventually, there will only be one survivor still standing if everything goes wrong, his back against the wall while facing the animated corpses of his former allies. In a survival round, the zombies team only has a certain number of reinforcements (lives), and when a zombie is killed they lose a life from the counter. However, when a human is killed they gain 1 life. When the zombies run out of lives, the remaining survivors win the round by killing off the remaining undead left on the map. In objective rounds, zombies get an unlimited number of lives while the humans must complete a variety of map-based objectives to win.