Zombie (monster)/Doom 3

Zombies in Doom 3 can refer to the general class of former humans and the most basic variant of these enemies.

The basic Zombie is a callback to the generic "George A. Romero zombies" (slow moving ghouls who feed on human flesh). They were UAC civilian personnel (i.e. maintenance workers, scientists, office workers, etc.) who were possessed by the demonic spirits from Hell, turning them into flesh eating ghouls.

A scripted event early in the game shows a scientist, Dr. Jonathan Ishii, coming into contact with a demonic spirit (in the form of a ghostly skull) which possesses him, turning him into a Zombie. The demonic force that creates Zombies does not differentiate between the living and the dead; slain humans will be re-animated as Zombies, and do not seem to be any less powerful than the ones created through possession of a living host.

Combat characteristics
Zombies come in somewhat different varieties, with some of them relying on wrenches and flashlights as clubs to compensate for more damage, or the Headless Zombie lacking a head, making them immune to headshots. While most Zombies are restricted to slow movement, some can occasionally limp, allowing them to close in on their victims slightly quicker than other Zombies.

Zombies are often seen hiding behind dark corners or in "monster closets" in order to surprise any unsuspecting victim in the vicinity. Some Zombies also play dead to catch their victims off guard.

Tactical Analysis
Zombies are ideal enemies to use the Pistol or the Chainsaw on. It takes around 6-8 Pistol bullets to the body to kill (a lot less with headshots) and a Chainsaw can gib through them in seconds.

On lower difficulties, players can solely rely on using the flashlight, as two hits can kill a Zombie. On higher difficulties, the player should swap for a Pistol as the Zombie's clawing attacks do more damage than an Imp's attacks. The flashlight can also alert any Zombies that play dead if the light shines on them. This tactic will save the hassle of being ambushed by one.

It is best to maintain a reasonable distance against Zombies, especially when fighting against them in hordes. As they are slow and entirely melee only, the player should never back down to a Zombie in most situations. The Machine Gun can efficiently take down a horde of them. If you find yourself cornered, the Shotgun can help turn the tides as one well placed shot at point blank range can kill multiple of them.