Hell is a cornerstone element of the Doom universe. It is the source of the demonic invasion in the games. It has a significant presence in many levels, and is the setting of parts of Doom, Doom II, Final Doom, Doom 64 and Doom 3.
Typical features of Hell in these games include copious numbers of mutilated bodies, some apparently still alive and presumably of the damned, and scatterings of Satanic iconography. Most of Hell's levels' architecture involves jagged rock walls, fire, wooden doors, stalagmites, dead trees and lava in place of nukage. Rarely does the player come across natural or technological aspects in the Hell levels, and indeed the structure of the levels themselves do not have any sense of flow or continuity.
In every Doom game Hell is depicted as having developed (or stolen from Earth and made quick use of) biocybernetics, implanting modern and futuristic weapons into many of its demons, in fact the cyberdemon and the spiderdemon are both powerful demons with mechanical and organic body parts, and the icon of sin appears to be an enormous, partially mechanical demonic head, though Doom II's endgame text indicates it has a suitably massive body as well.
"Zombies" in Doom are often regarded as "former" humans possessed by demons from Hell. In Doom 3 it is demonstrated that both dead and living humans can be possessed, but in the Doom novels, where Hell is not a part of the story, it is indicated that only dead humans can be made into zombies, and the Doom Bible had possession happen to living but sleeping humans. These zombies also lack a soul after a given amount of time, as the Artifact cannot absorb a soul from a downed enemy that was a zombie, although it can take souls from any other bodies and in one instance it can take the soul of a man during the game who becomes a zombie in front of the marine and is killed.
In Doom 3 most of the civilian and security personnel on the base are possessed and converted into zombies in the first wave of the demonic invasion. For unspecified reasons, however, some characters - notably the Nameless Marine (the Player) - are not taken over. Councilor Swann, Jack Campbell, Sergeant Kelly, along with a handful of marines and civilians are also amongst those not instantly converted into zombies.
Through out the game, the Marine experiences instances of blurred red vision - usually accompanied by evil laughter or demonic language. Early in the game, when the player looks into a mirror, he sees a vision of himself starting to turn into a zombie. These events are possibly the result of the demons' (unsuccessful) attempts to possess him. This, coupled with the fact that quite a few of the base's military personnel were initially unaffected by the demonic invasion, suggests that the demons cannot possess those with strong, well-disciplined minds (or at least have difficulty doing it).
A second process of zombification is also referred to in Doom 3 in which the victim is slowly driven insane by a mysterious ailment. The victim suffers from hallucinations and voices, and becomes increasingly hostile towards those around him. Physical changes occur only at the end stage. It is unknown whether this is the result of a virus or some kind of spell. In any case, this insanity can only be contracted in Hell.
Access to Hell
In the games Hell is discovered following experiments in teleportation technology, and during gameplay Hell is only accessible by long-distance teleporters or gateways. In the original Doom teleporters notably have Satanic symbols on them. In Doom 3, it transpires that teleporter technology was derived from documents left behind by an ancient Martian race.
Hell in Doom is heavily based on the religious concept that "bad" people spend eternal damnation in Hell after death. This is indicated in the Doom II endgame text, "You wonder where bad folks will go when they die now," and again in The Plutonia Experiment's endgame text, "Hell has gone back to pounding bad dead folks instead of good live ones." However, the player is not visibly sent to Hell when he dies: the player must continue the game from the beginning of the level, or from a saved game.
Because one cannot physically travel to Hell without the aid of some sort of gateway, Hell's actual location is never revealed, though it is indicated by the Doom FAQ and by the unusual behavior of the environment in Hell in Doom 3 that it is not a part of our universe but rather another dimension entirely.
Differences between games
While the major Doom games all depict Hell, the theme changes slightly between games. The variations between Doom and Doom II are based mainly on levels created by different designers. Doom 3's Hellish atmosphere departs more strongly from the original games.
The original Doom's Episode 3, Inferno, entirely takes place in Hell, where it is depicted as predominately brimstone-covered with a fiery sky, complete with a demonic cathedral and pools of blood. Walls and floors occasionally appear to be made from body parts including human skulls, intestines, spines and skin. In the PlayStation version, Hell's sky is filled with flames, while the Saturn version's stages have a city skyline.
The game's box art and the ending screen for The Shores of Hell both depict rocky, barren landscapes.
Thy Flesh Consumed takes place on Earth immediately after the player's return from hell, as evidenced by its endgame text and the episode's resemblance to Inferno's ending sequence. Until the episode was released, the first level to take place on Earth was MAP01: Entryway (Doom II).
In the original Doom, Mars's moon Deimos provides the first link between here and Hell.
In the storyline approaching the beginning of Doom, military experiments are conducted between the gateways at UAC facilities on Phobos and Deimos. Something went wrong, and "soon afterwards, Deimos simply vanished from the sky."
Deimos's mysterious absence is referred to in Knee-Deep in the Dead's ending text, after the player steps through the gateway at the end of E1M8: Phobos Anomaly: "It...looks like the lost Deimos base." It is later revealed at the end of Episode 2, The Shores of Hell, that the entire moon had somehow been transported to Hell, which would no doubt account for the complexes being seemingly warped and taken over by demonic means more so than the Phobos installations. The gateways, still functioning between Phobos and Deimos, provided the first entryway into Hell.
Doom II's Hell levels are often closer to subverted human buildings, with the exception of the last three levels. However, map 28 is not exactly Hell, but rather the pathway from Heaven, Earth and Hell, like Limbo (hence the name). The sky in these levels (where there is any) contributes heavily to the Hellish atmosphere.
Final Doom's portrayal of Hell does not deviate much from previous depictions, and seems to be a combination of the original Doom's cavernous areas and Doom II's building-strewn stages. Hell levels have two different skylines; a "nightmare" red sky in TNT Evilution and a crimson sky that looks like stretched, bloody muscle (the end of level tally screen background) in The Plutonia Experiment.
Doom 64's Hell levels take a dark, cavernous, and frightening approach. There are two separate types of Hell environments: rocky, volcanic areas with a burning red sky and mountains, or similarly-themed mountainous areas with dark blue storm clouds, complete with thunder and lightning. The architecture found in most of the levels resembles castles, cathedrals or temples, replete with vicious Satanic and horrific symbolism, including plentiful pentagrams, inverted crosses, and blasphemous altars. Various human remains are strewn about these levels, including impaled heads, butchered carcasses on meat hooks, and splattered corpses on the ground. Later levels possess a skyline of burning red or green fire against a dead, black sky.
In Doom 3, the player ventures into Hell to obtain the Soul Cube. Hell is largely a claustrophobic and cavernous plane with crimson blood sky (it also resembles outer space to some extent), both dark and fiery (although "outdoor" sections do appear). Mostly, Hell takes place in a large castle-like area, finished with huge stone bricks, broken cell gates, glowing Satanic glyphs and pentagrams, and huge oceans of magma. The conventional rules of physics are frequently violated. Unlike in Doom, the atmosphere in this Hell is almost constantly noisy, typically with the crying and moaning of damned souls and extreme sizzling and bubbling of hot magma. People who enter Hell tend to experience a surge of physical energy much like that of an Adrenaline rush: seemingly able to continually exert themselves without tiring. Dubbed the "Hercules Complex" by researchers, this effect is noted in the game by the player having an infinite stamina gague (with flames shooting through it) while in Hell.
Doom 3: Resurrection of Evil
In Resurrection of Evil the Marine takes a journey to Hell to return the artifact in order to stop the invasion. This area of Hell is different than the one explored in Doom 3, although there are plenty of similarities in landscape and architecture. The area where the battle against the Maledict takes place is an eroded floating island in a sea of sizzling magma.
Doom without Hell
One of the primary criticisms of the Doom novels is that Hell was cut out and the demons became aliens genetically engineered to scare humans instead.
A similar criticism was aimed at the Doom movie, where the monsters were humans mutated by a Martian gene splicing experiment, and universally lacked the projectile attacks of their game counterparts.