• animals have turned into zombies too
• the zombies learn how to swim, drive, or fly
• the zombies learn how to search for you
• there's no way to kill them including blowing them into tiny pieces
• zombies begin to breed
• there's nothing but zombies as far as the eye can see
• you have one round left
• the zombies begin to form unions (i.e. the United Federation of Zombies)
• when nothing can stop them including steel doors
• they can communicate with each other through telepathy
• Zombie Ninjas