Your job in this virus chain reaction game is to create zombies that will attack and infect other humans running around the area. First you start off simply by dropping an infectious DNA string on a human or a grouping of them to change them into zombies. At that point they will come back to life and chase down and attack the others that are not infected. There are police officers and various different resistance fighters that will kill your zombies though so you need to drop grenades on them so they will not kill off the chain reaction you have just created. From city to city and country to country you need to dominate the entire world with your virus and put an end to humanity!