According to Gallup polls, somewhere between 60 and 70 percent of Americans believe Hell is real, and some believe it's an actual place that one can go, not a state of being or a metaphor. Of course, the game Doom runs with the idea that Hell is an actual place, complete with fire, brimstone, and bloody viscera in another "dimension" that one can reach—ideally with a double-barrel shotgun.
Spoilers for both Doom 3 and Doom 2016.
In the 22nd Century, humanity has colonized the Solar System, and the ruins of an ancient civilization were found on Mars. The United Aerospace Corporation—a Weyland-Yutani analog—reverse-engineered some of the Martian technology and deciphered some their theoretical physics, leading to new forms of energy production, teleportation, and methods of faster-than-light travel. Doom 2016 expanded on this further with the UAC discovering a spacetime "tear" in a Martian trench that provides a fount of exotic energy called "Argent plasma". Unfortunately, the UAC ignored the many warnings the Martians left, and they soon learned that the teleporters open wormholes to Hell (called hellholes in the game), thereby letting demons invade the UAC facilities and eventually Earth, unless of course the player—a nameless tough-as-nails space Marine—can stop them first.
There is actually some theoretical basis for "higher dimensions" and parallel universes, such as brane cosmology. Our 3-dimensional universe may be restricted to a "membrane" that exists within a "bulk", a higher-dimensional space often called hyperspace or subspace in science fiction. However, the term "dimension" is usually misused in science fiction games like Doom. The higher dimension (probably 5th in this case, the 4th being time) isn't an alternate universe, it's how one would get there. For example, if we removed a dimension so that 3-dimensional space were reduced to the 2-dimensional surface of a sphere (the "brane" we live on), the "higher dimension", or bulk, would be the 3-dimensional volume within the sphere. Doom's teleporters would work by creating a shortcut through the sphere from one side to the other, like a wormhole through an apple, hence the name. Doom's Hell could be a void—imagined in Doom as a sort of spacetime prison for demons—that the teleporter shortcut runs into, allowing the monsters it contains to escape like liquid from a punctured container. Coincidentally, this resembles Dante's medieval conception of Hell which was believed to consist of concentric circles beneath the surface of the Earth. id could run with this dimensional analogy and even include the Nine Rings of Hell (alluded to in-game) by making them a series of nested, concentric "spheres" within hyperspace. The most recent game has "realms" of Hell that can only be accessed through portals, so the basic elements are already there for the developers to expand upon. Some of the architecture in Doom 3 seems to incorporate higher dimensions, as the player will often enter buildings that are much larger on the inside than on the outside, or pass through portals that teleport the player instantly from one point to another within the same building. If id borrowed some of these concepts from cosmology, it might give the series a degree of verisimilitude. Though, if the 2016 entry in the series is any indication, id seems to be moving away from the serious, "realistic" tone of Doom 3 and in a self-aware, deliberately cheesy direction.
|The rings of Dante's Inferno (image from Wikipedia)|
|This guy would probably pass as an alien in another sci-fi setting (image from the Doom Wiki)|
In place of a Garden of Eden origin for humanity, we find that anatomically modern humans are at least partly descended from an extinct Martian civilization, which is a backstory rather reminiscent of Halo, Alien, Battlestar Galactica and other "ancient aliens" stories. I find the "ancient astronauts" trope annoying, personally; it's rooted in the myth that human origins are still a great mystery, when it's rather obvious that humans are primates who evolved on Earth. However, I find it a little more tolerable when the same fictional universe has what appears to be the Biblical Hell within it—it would make less sense if there wasn't some sci-fi connection to angels and gods too. Evolution and these ancient aliens ideas aren't incompatible, as Halo showed. Our species is much older than many realize, at least 200 thousand years old. There's more than enough time for some "uplift" scenario to produce a prehistoric human civilization on another world. Applied to a film like Prometheus, this would mean the Engineers came from us rather than the other way around.
Doom 16 expands on this ancient astronauts idea further by revealing the apparent fate of the Martian Civilization shown in Doom 3. While originally announced as a reboot, Doom 2016 appears to be a "stealth sequel", or soft reboot, as player's can find artifacts, relics, and tablets that allude to the fallen Martians of the prior game. In Doom 2016 the player character, known as the "Doom Slayer" by the forces of Hell (the game tries to be Metal af), seems to be an ancient astronaut, or in this case, and ancient space marine. It's implied that he was a Martian warrior who migrated to a world called "Argent D'Nur", a world that was later conquered and assimilated into Hell. Some fans speculate—based on the appearance and markings on his armor—that he is the Marine from the original game who has been either universe jumping or time traveling like Ash from the Evil Dead films. Which actually seems rather fitting given Evil Dead along with Aliens was the original game developer's source of inspiration.
|Doom Slayer on an ancient demon wood carving battling alongside his space knight comrades (image from Doom 2016)|
—For an accessible and enjoyable book that explores bulk beings, travel through higher dimensions, and wormholes, I recommend Kip Thorne's The Science of Interstellar.