"INFECT THE WORLD. A strange virus has appeared in New York City, turning seemingly normal people into insane, violent Zombies! Cleanse the streets of mad, flesh-hungry INFECTED. Lay out defensive units and prepare for the Zombie onslaught in this twisted strategy-defense game with campaign or multiplayer modes. Set defensive lines from a selection of fighting and vehicle units including NYC Cops, Muggers, Oil Tankers and more. Be quick these Zombies wait for nobody
SPREAD YOUR UNIQUE ZOMBIE VIRUS THROUGHOUT THE REAL WORLD: Customize the appearance and effects of your on screen Zombie to taunt your opponents on your mission to infect the world
MULTIPLAYER ATTACKS: Infect other players by winning up to 4 player multiplayer matches. Watch as you spread your virus to friends and enemies from all over the world!
BUT YOU CAN SAVE YOUR FRIENDS TOO! You can also choose to protect all your Facebook, Gamecenter and Openfeint friends from oncoming zombie attacks to gain even more experience"
Source: The Game Website.