But, as a preview, here are the descriptions of all the different types of zombies.
Shamblers are your classic walking corpse. Reanimated by some horrible, infectious force, their bite turns anyone slain by a shambler, into a shambler. Contrary to popular opinion, shamblers do not eat their victims. They simply bite and pummel them to death in order to create more zombies.
Sometimes called “fast zombies” or even “zoombies”, savages are people infected with the SAVAGE virus. They are NOT undead. The SAVAGE virus destroys all intelligent thought, turning the victim into a blood spewing maniac.
No one is sure where the brain slugs come from. Smart money is on outer space, either in a meteor, or possibly an alien teenager's science experiment run amok. Whatever their origin, brain slugs crawl into the brains of recently deceased or living humans through any convenient orifice or wound, turning them into slug zombies. If that weren't bad enough, they multiply in the brain.
Science run amok! Z-troopers are the military's attempt to make a perfect soldier that obeys all orders and doesn't feel pain. Well, they were half right. At least they don't turn people into zombies. Did I mention they're radioactive?