Mercenaries vs. Zombies is a tower defense game set in a zombie apocalypse. You must prevent hordes of zombies from exiting the area by placing mercenaries on top of towers and calling in air strikes. Each mercenary is armed with a pistol, grenade launcher, or bow and arrow, and each weapon has its own strengths and weaknesses. When you complete a level, you'll earn stars that can be used to upgrade your mercenaries and air strikes.