Valve Game Studios has produced two popular and critically acclaimed video games franchises that feature zombies prominently. The first was Half-Life, where a type of alien parasite known as a Headcrab could take control of its host. The second series was Left 4 Dead, a successful attempt at creating a classic zombie film atmosphere, whereby the players are simply trying to find sanctuary in a zombie apocalypse.
Once a Headcrab successfully attaches to a host, the Headcrab will assume control of all their motor functions, able to walk and attack with the host's arms and legs. Through some unknown biological process, the host's hands turn into long, skeletal claws and a massive hole appear in their chest lined with the hosts' ribs, becoming a makeshift "mouth", with their ribs serving as teeth (zombies have been observed to feed by ripping chunks of flesh off of corpses and stuffing them into this maw) Removal of the Headcrab reveals that the host's head is bent abnormally upwards, their hair is matted with blood, and their face is pale, with their eyes shut and mouth open in a frozen scream. In Half-Life 2, the muffled pleas and screams coming from the zombies indicates that the victim may be somewhat aware of their zombified state and obviously in an unimaginable amount of pain the entire time.
Occasionally, Headcrab zombies may survive losing both legs and their lower torso, and continue to crawl along using their arms. In most cases, a Headcrab remains attached to its host until the zombie is destroyed, although in Half-Life 2, they will occasionally detach from the host if it is rendered immobile by its injuries.
Other types of Headcrab Zombie include the Fast Zombie, Poison Zombie, Gonome, and Zombine.
Left 4 DeadEdit
The Infection is an aggressive disease of unknown origin that provides the backdrop (and antagonists) for the hit video game Left 4 Dead, which is comprised of the original and its sequel. Unlike the classic undead zombies, infected are technically still alive, but both the zombies, and the virus are still dangerous enough to produce all the social and economic devastation associated with the Zombie Apocalypse. On some warning posters within the second game, the Infection is referred to as Green Flu.
The Infection can mutate its victims both mentally and physically. The Infection is also only capable of infecting warm blooded animals, with some theorizing that it is a mutated strain of Rabies. The means of infection is theorized to not only be through bodily fluid transfer (such as bites) but perhaps even airborne (as per Valve's comic The Sacrifice). This would indicate the virus may have a very long incubation period under some circumstances. In addition, some humans seem to be completely unaffected by the virus, even after being bitten; it is possible that a vaccine could be made from the blood of these immune individuals. But the Survivors who are immune can still spread the virus.
The Normal or Common Infected, or the "Horde," is a normal mutation from Human to Infected. They are extremely similar to the type of fast zombie seen in the film 28 Days Later. They are excellent climbers (more so than the Special infected), and seem to be evolving better attack paths to their target, instinctively bobbing and weaving around incoming fire. Without a target, a dormant infected will shamble along aimlessly, spreading out from one another over long periods of time. They will often curl into a ball with their heads against their knees, lean against walls as if exhausted, vomit, fight each other, and sometimes even lie down and simply die by themselves. This can be seen as an indicator that the Infection may not give its hosts a particularly long lifespan. Once a target is found (either visually, or enticed by loud high pitched tones or beeping sounds. A large amount of gunfire will send an attack at any given time), the infected sprints to attack its prey. Like most depictions of infected, they do not consume human flesh. While biting attacks are usually common, normal infected rarely, if ever try this maneuver on humans with an immunity to the infection. Instead, they prefer wild hand-to-hand combat, grabbing, smashing and stomping their target to death. It is the grabbing, the hindrance to a survivor's mobility that is their greatest weapon, splitting up groups that don't realize some parties are unable to keep pace.
Uncommon Common InfectedEdit
These infected (sometimes referred to as UCI's in survivor circles), either through a slightly different behavior, or through occupational circumstances prior to infection, have slight advantages over common infected, and pose additional difficulties to survivors they encounter.
- The Hazmat suitted CEDA scientist infected is immune to fire. There are great numbers of this sort of UCI in and around Savannah, Georgia, where a large evacuation point and research facility fell to the infected hordes. Whether the scientists were infected prior to equipping their hazmat suit, or whether small bites transmitted the infection, yet maintained most of the suit's integrity is unknown.
- Fallen Survivors were not immune and they became infected. They still carry the supplies they had prior to being a zombie. They attack the humans but when they are attacked they run away.
- The Clown infected draws other common infected to his side with each step of his squeaky shoes. He also seems to have a constitution comparible to a special (boss) infected. These are rarely found outside of circuses or them parks, such as Whispering Oaks Amusement Park.
- Mud Men are rural swamp dwellers, usually of foul hygiene and disposition even prior to becoming infected. Mud Men have a very low pursuit and attack stance, often barely peaking out under swamp water. They also throw handfuls of mud to distract their targets before physically engaging them.
- Construction Worker infected still don the noise cancelling headphones from their jobs working with heavy equipment. They cannot hear the tones of the standard pipebomb lure. These are encountered near construction sites, neighborhoods undergoing economic revitalization projects, and industrial zones.
- Riot Gear infected turned while wearing the kevlar reinforced heavy riot armor they used to suppress outbursts of infected (and fleeing or rioting human mobs). As such they are impossible to damage from the front. Killing attacks must be made from behind. These are in greatest numbers in metropolitan areas where the government attempted to make a stand, but was overrun, such as New Orleans.
- Jimmy Gibbs Jr., the famous race car driver, also has a 5% chance to spawn during the Atrium Finale. He will appear in his infected form. Unfortunately for the survivors, he has 1000 health, is immune to fire, and has a motor-oil blinding effect upon attack. He can be killed instantly with a headshot, because his head is not protected by his racing suit.
One innovative aspect of Valve's Zombies is their capacity for mutation. Unknown variables in the host's body cause a small percentage of infected parties (less than 1%) to develop dramatic (and horrific looking) bodily mutations. Known as Special Infected, Boss Zombies or Boss Infected they include The Hunter, The Boomer, The Smoker, The Charger, The Jockey, The Spitter, The Witch and The Tank. The Witch and The Tank are the bosses with the most potent and radical mutation, in terms of measurable boost of power over the human condition. As such, they are the only two bosses that can sustain vast amounts of damage. All other infected are notably frail. Even the seemingly stalwart Hunter can be killed with several well placed pistolwhips. All forms of the infected are very vulnerable to the effects of fire, with many types perishing mere seconds after contact. It is likely Valve's implemented the mutation concept to the game to give varied play experiences to infected players, and also to capitalize on the class based team approach popularized in first person shooters, as well as massively multiplayer games. All infected are more susceptible to headshots than wounds elsewhere, with the notable exception of the Tank, whose cranium is likely too thick to be affected by common ballistics.
The Hunter is an agile type of Infected which can jump from one place to another from long-range distances. It has mutated short clawed fingernails, and adopted a crouched posture, crawling about on all fours, at times, not unlike a dog. Though their claws are small, they are able to use them to a deadly effect, cleaving flesh with ease. They use their agility to their advantage, letting out a primal screech and pouncing on top of victims, mercilessly tearing away at them until someone knocks them off. It is also silent when not leaping, allowing it to sneak up on prey much more easily than its fellow Infected. Lastly, Hunters are blind, with all defeated specimens noted to be missing their eyes; this has little bearing on their ability to locate and hunt prey.
The Smoker is though taller than most infected, and is covered with a large amount of tumorous sacs and pustules. A faint green smog can be seen around them, which is what gives them their name, along with the coughing noises it makes. The main weapon of a smoker is its long prehensile tongue. It uses this tongue to ensnare and asphyxiate its prey from a distance. It tends to position itself on rooftops, or higher than its perceived targets, to add effectiveness to its ambush. It is unconfirmed whether the extreme length of this tongue (roughly 30 ft) is due to the mutation joining the tongue with the smokers digestive tract for additional length.When a smoker is killed, they will explode into a cloud of green gas, obscuring the vision of survivors and impeding their breathing, causing coughing. Long term effects of smoker cloud inhalation are unknown.
The Boomer is a large, grotesquely bloated infection form. It moves in a sort of slow hobble, and is rather easy to see from a distance. They make wretching sounds, causing them to be heard from a distance much like the Smoker.The Boomer's bloated belly is filled with enormous gas pressure, as well as thick green bile. The pressure makes it one of the most fragile infected, as it can burst like a balloon(If the Boomer falls of something high above the ground, it will burst & die on it's own). The bile, however, constitutes the Boomer's main form of attack. The creature vomits all over its victims, heavily obscuring their vision. Even worse, the scent of the Boomer's vomit immediately attracts large amounts of normal infected to the near-blind victim's location. This bile will also fly surprising distances upon a Boomer's death. When the Boomer explodes, the bile will do the same as its vomit. As such, close combat is highly discouraged. CEDA managed to obtain samples of the bile for research purposes. Sample jars made of glass containing treated boomer bile "bile bombs" are found throughout the campaign, usually carried by infected CEDA hazmat personnel. These "bile bombs" once thrown at a group of Infected will cause themselves to attack one another and provide an opportunity for the survivors to escape.
The Tank is a massive variant of the Infected strain which has drastically mutated the body of the Infected into what looks like the undead equivalent of the Incredible Hulk. Its arms are thick like tree trunks and become long enough to touch the ground, giving the Tank an ape-like posture. Its legs are smaller than a humans, and as such, it uses its arms to assist in walking and pursuit. It is nicknamed for its incredible constitution, and notorious for its incredible brawn.While Tanks have rarely been observed in dormant, resting states, it mysteriously seems to have a much larger radius of perception, beginning it's assault charge from dozens of yards away. This is known by the rumbling of the ground created as it sprints. It attacks much like a normal infection form though moving in a slower, lumbering manner, at its target. However, it also uses the environment as a rudimentary weapon, using its phenomenal strength to sling cars or even rip large chunks of concrete out of the ground to toss. Tanks can also take an incredible amount of punishment before their body shuts down: even several point blank shotgun blasts will leave the creature unphased. As mentioned before, headshots have been verified by skilled survivors to have no discernable impact. Luckily, its increased muscle mass (somehow) makes it highly flammable and will die in less than a minute if set on fire. Tanks appear in much fewer numbers than even the other Special infected.
The Witch is unique in that it is not naturally aggressive. It bears a resemblance to the normal infection form, but its eyes glow a potent red bright enough to light up her surroundings slightly. She also has claws, much like the hunter, but much longer, reaching around five inches from her fingertips. The Witch can be easily heard from a distance because she is constantly sobbing. The reason for this is unknown; It may be that Witches have some sort of intelligence left to them (indicated by their ability to still cry) and can feel the pain of the infection in their body. Alternately, it could be a ruse to lure in would-be rescuers to their death. The Witch will not act aggressively towards survivors, taking no heed of any combat around her as long as the survivors do not cause her to feel threatened. For this reason the best plan of action is often to circumvent the witch entirely by taking a different route. Shining a flashlight on the witch, going to close to her, or shooting at her will cause the witch to stand up, growling in a threatening manner. If the one that she feels threatened by does not leave her alone, she will lash out with a banshee's wail, slashing at the victims innards until there is little else left. Despite her small frame, her physical strength and durability is comparible only to the Tank. The Witch is the most powerful form of the infection in terms of hit lethality, able to incapacitate targets even easier than the Tank, despite its much more spry appearance. It is also the second most resiliant species, able to take quite a lot of hits before succumbing to its injuries, though not as many as the Tank. Unlike the Tank, rounds that penetrate the skull will cause additional damage, but large chunks of the brain can be damaged, yet the witches assault may continue.The Witch is the only special infected that cannot be controlled by a player because it would be easy for players to destroy the entire Survivor team. Also on some occasions the witch can kill instantly instead of only incapacitating in one hit. When the witch does kill her target she looks around and runs away crying.
Newer Special InfectedEdit
The following three Special infected evolved 4–8 weeks after the initial outbreak, and seem to be found in the highest concentration in the Southern United States. These newer infected mutations are also unique in that they have their pupils intact, though the cause or significance of this has yet to be determined. Regardless, future infected mutation may continue as time goes on.
The Charger Infected is much like the Tank Infected with the exception that only one of the arms on the Charger is muscular and is used when attacking the enemies in an attempt to split them up, while the other arm is weak and tiny, drained of all muscle, and therefore hangs limply. Its legs are thick and strong. As its name suggests, its primary mode of attack has it charging into survivors, which it will pick up and slam into the ground. The charge is easily avoided, though, and survivors can trick the Charger into running off a ledge without much difficulty. The Charger also has an unusually high sense of balance and body positioning, and cannot be shoved off balance like most other infected.
The Spitter Infected is an Infected which has a strain of the virus which is very similar to the Boomer strain, which makes the host able to generate and project a fluid as an attack. But the difference is that the Spitter has acidic spit instead of a bile which attracts the horde. The Spitter has an eroded mouth (no teeth, missing her lips etc.), an elongated neck, a distended belly and long limbs. Its acid is highly corrosive and will hurt any survivors that come into contact with it. The fumes that rise from the acid pool are also corrosive, breathing within 3 feet of the acid (from above the acid pool) will cause severing burning of the lungs, and may lead to pulmonery edema.
The Jockey Infected is small, hunchbacked, wirey, and notable for its maniacal laugh, and gnawed-away lips and chin. It's preferred mode of attack is vaulting onto its prey's shoulders and head, and attacking the head and face with a variety of punches, scratches, hair pulls and a tight leg scissors. Jockeys seem to have a great understanding of human behavior and reflexive reactions to pain, as they are adept at using their harassing and blinding attacks to almost steer their victim to more perilous locations, such as over edges, behind walls, into hordes, into spitter acid pools, and into any nearby witches.