Zombies are caused by capsules, with black figure and white eyes; they have brought about the end of civilization and remain a constant threat to anyone exploring derelict stations. They come in several flavors:
- The basic zombies is barely a threat on its own, but usually appears in greater numbers. Takes four empty-handed punches, one fully charged punch, three melee hits with the shotgun, two bullets to the body, or one bullet to the head to kill.
- Smaller zombies or tacklers have the ability to run and bite, can easily overwhelm the player. They are about half the height of a regular zombie.
- Armored zombies wear grey bulletproof armor and a face mask that protects their head and torso but their legs are still vulnerable. Needs a punch to knock off the helmet and a headshot to kill. They will be most of the time found in factories, military facilities, and other random points
- Explosive zombies will, as the name implies, explode upon death or contact with the player, dealing huge area damage. If shot but not killed their heads will light on fire and they will explode after a short time.
- Titans or tall zombies are like magnified basic zombies, and need more shots or punches to kill them, they will appear to be a threat due to their high hits and takes 2 good punches to kill them.
- 2 New variants of Titans come into the Only Traitor DLC: Crawlers and Frenzies
- Crawlers are a titan variant that can be shot with 2 - 3 bullets, but they well crawl their way to the players feet and swipe after they go down, making it difficult for the players to kill in the line of sight
- Frenzies are a titan variant similar to a combination of the original and tacklers, shooting a frenzy will make their eyes glow and run towards the player doing a massive amount of damage in 1 - 2 hits killing the player. It take 5 - 6 shots to kill them.
- Jumpers will pounce the player, grab on to their face, and prevent weapon firing while biting. They appear quite similar to the smaller zombies. Has long arms that reach the floor, short legs, and what appears to be long hair coming from its head, leading many to believe these were female or possibly even children.
- Note that all zombies can be killed with an explosion from an explosive zombie or barrel, or from a hit from a thrown object.
- Acid Zombies can pose a threat to players that they can spew globs of Acid towards the players direction from far to medium distance, they will also hit the player in close combat. It takes 3 - 6 shots to kill them. They have same features as of the others but with a green glow in the eyes and mouth.