You have two heroes you can choose from while playing this online game featuring zombies, zombies and even more zombies. The other hero is self-controlled and he or she will be fighting against the zombies along with you. It is believed that the zombie infestation is spreading fast through their smoke. You must quickly position yourself on the wall and start blasting off the zombies using the weapons in your hand. Each shot will earn you money that you can use to make purchases of better weapons, defenses and specials that help you become even more effective against the newer and perhaps more powerful waves of the evil creatures.