In Quake 4, there are two types of Zombies: Slimy Transfer and Failed Transfer. As their names suggest, they're partially Stroggified humans deemed unusable by the Strogg and more or less dumped into the Waste Facility and forgotten about. Slimy Transfers behave like typical zombies; they puke acid and eat flesh. Failed Transfers are shambling, partially-stroggified humans armed with a Shotgun. Both types were made by botched attempts at Stroggifying humans and were sent to the Waste Processing Facility to be destroyed, both can still pose a threat even when they are cut in half. Some are contained in green barrels, if you see them opened or being opened in areas like the Waste Processing Facility, expect to meet the Zombies.
The Zombie types appear as a player model in multiplayer.
- Slimy Transfers are cannibalistic, partially stroggified humans covered in thick slime. This caused them to make moans. Slimy Transfers will puke acid at you even if you aren't right in front of them. This acid has very long effective range and will inflict damage continuously even after you've been hit, making it really painful. To prevent this from happening, get close so that it'll use it's melee attack on you. The melee attack does less damage, while getting close to it puts it in range to be blown away by a Shotgun. When attacking it, aim for the head, as headshots do twice the damage.
- Slimy Transfers are occasionally packed into green barrels and will crawl out of them when you get close, so be cautious around barrels, especially the open ones, in the Waste Processing Facility.
- If you run into them at close range, shotgun, Hyperblaster and Machine Gun can be used, remember to aim for the head or the chest, this will kill them faster, using explosives can hurt yourself, Railgun and Nailgun are too slow, so they are not recommended.
- With other enemies, the Slimy Transfer should be one of your first targets. Its acid puke can hit you from nearly anywhere, you are not really safe unless you are out of its sight. The damage from the acid can still hurt you even after it hits you. They are slow to avoid most projectiles, so dispatch them with Hyperblaster is a good idea, machine gun also works at medium range.
- They also make moaning noises more often than their Failed counterparts, so you can tell where they are easier.
- Failed Transfers behave like Shotgun Guards and Tactical Transfers who wield Shotguns, but are much slower. A few Blaster shots should finish it off in no time, especially if you aim for the head.
- With other low-level enemies, the Failed Transfer is cannon fodder. Its speed makes it easy to run away or get out of their sight if it's getting too close, and it's Shotgun will do little damage if it isn't close to you.
- Be careful; sometimes it's torso will detach from the rest of its body if it takes enough damage. While very comical looking, the torso will lunge at you if it gets close enough, inflicting a good amount of damage. Again, a few shots from the Machine Gun or Hyperblaster should put it down.
- Don't be startled by the random hop and quickly dispatching them. Otherwise, they will overrun you, even if there are multiple instances of them trying to kill you, you can rely on heavier weapons like the Nailgun or Grenade Launcher to get you out of trouble if the situation is critical.
- It's a mystery why all Failed Transfers are armed with Shotguns, considering that they are failed Stroggification experiments. Furthermore, it's unknown why the Shotgun is the only weapon they carry.
- It's unknown what the slime on Slimy Transfers is, or why they have the ability to puke acid.