"By Hell's law, if the Dark Lord is defeated in ritual combat any demon outside his realm will be destroyed."
--The Father, Doom Eternal: The Ancient Gods - Part 2
DLC campaign additions to single player games can reach great heights. Minerva's Den from BioShock 2 and Whistleblower from Outlast exemplify how naturally they can flow from the narrative of the base game. Doom Eternal's expansion campaign The Ancient Gods fits into the same general category, although the extreme difficulty of certain parts even on the default difficulty setting (the second lowest) could frustrate some players enough to stop playing altogether. The Ancient Gods is primarily a story DLC--it does not provide access to a grand array of new weapons. It does get to expand the somewhat theological lore of the reboot Doom games and go as deep into the metaphysics of the series as has ever been done. Yes, there is even a pseudo-uncaused cause that is introduced. From the new Spirit enemy type to the Seraphim to the enigmatic "Father" credited with creating Urdak, Hell, and the universe as a whole, the theological words, and in some cases concepts, behind the reboot games are placed at the forefront from the start.
Production Values
As a PS4/Xbox One generation console release from 2020 ported to the Switch, The Ancient Gods could have looked far worse. The returning motion blur from most of Bethesda's first-person shooter Switch ports interferes with precise screenshots and sacrifices some visual clarity, but the graphics are fairly strong given the context of where the base game and DLC originated. Visual variety can be easily found as well. From the Kaminoan facility-like structures protruding out from the ocean in the first level of Part 1 to the Avengers: Endgame-like final showdown with portals in the last level of Part 2, the level design changes very distinctly with every mission. The story, after all, leads the Doomslayer from Earth to Urdak to the new location Immora, the capital city of Hell. This lore-heavy plot contains a great deal of voice acting. Thankfully, the speaking characters receive just as much effort for their voice acting as the characters of Doom (2016) and the base game Doom Eternal do.
Gameplay
Other than the addition of a few enemy types, most notably the bosses, Spirits (which feed into the enormous challenges of just surviving the later levels), and variations of previous enemy types with new abilities, the gameplay is very similar to that of the core game. The environments receive the most variation, with the opening level of Part 1 of The Ancient Gods taking place on a facility elevated above the ocean, the second in a fog-filled part of Hell, and the third in a fallen Makyr city, and so on. You can still both gain and lose health, shield pieces, and ammunition very quickly. Collectibles and 1-Up (or 2-Up) pickups are still scattered around levels. Slayer Gates likewise return as optional enemy fights in a confined location, but now completing them awards the player Support Runes, of which one can be selected on top of the other runes from the non-DLC campaign. The small benefit of the equipped Support Rune is at least something to help with the extreme combat. Another small benefit comes with the new Sentinel Hammer, the only novel weapon, which smashes enemies to produce ammunition and health/armor if they are frozen or caught aflame. This melee object can be upgraded with its own optional challenges.
Yes, the core gameplay mechanics have undergone little change since the main game besides these occasional additions, but one thing has: the difficulty. The Ancient Gods is the toughest Doom experience yet. Little can rectify issues related to platforming, exploration, and non-boss combat besides practice or luck, but the optional Sentinel Armor provides a massive advantage in boss fights. Unlocking as a temporary aid once a player dies multiple times, it drastically reduces the damage when fighting bosses like the Seraphim. Continually dying when boss fights switch to phases where the boss itself is inaccessible can even trigger an automatic skipping of those sections after one dies enough times (yes, I learned this from direct experience). In general, The Ancient Gods can be absolutely brutal in almost any combat situation without the Sentinel Armor, offering a far more challenging set of missions than the primary campaign does on its own. This is most evident in the later missions when the expansion throws wave after wave of Doom Eternal's strongest foes at the player, with a Spirit possessing/empowering them (and Spirits can only be killed using a specific weapon attachment).
Story
Some spoilers are below.
The Doomslayer has defeated the Icon of Sin and Khan Makyr, but the victory has allowed demons to infiltrate the Makyr city of Urdak. Samuel Hayden and a group of human allies guide the Doomslayer in a quest to find the Seraphim, an angelic companion of "The Father," who is in turn said to be the supreme being in existence and responsible for creating the first beings beyond himself. There is also a Dark Lord who needs to be summoned in physical form so the slayer of Khan Maker can destroy it forever. If this Dark Lord dies, all the demons of Hell, formerly known as the advanced city of Jekkad, will perish as well. This revelation and several others push the Doomslayer to a climactic confrontation with the Dark Lord for the sake of the universe and all living, non-theistic creatures besides angelic and demonic aliens--but the Dark Lord has secrets of his own to bring to light.
Intellectual Content
The philosophical potential of telling a story where Hell, or at least the Hell of the Doom series, is just a realm called Jekkad in another dimension at war with the realm of Urdak, or Heaven, is vast. This potential only compounds when the actual uncaused cause is discussed and makes an appearance--with a major narrative twist. A literal deity, the angelic aliens of Urdak, and the demonic aliens of Jekkad all appear in The Ancient Gods. The issue is that the 2016 reboot very blatantly set the full lore and associated themes aside, which made Doom Eternal have to introduce the more exotic but foundational metaphysics of the series alongside its sometimes satirical, ironic lines. The Ancient Gods then introduces even deeper lore that comes too late to shift the series as a whole to explicitly philosophical waters despite the surprisingly theistic revelations.
Ironically, the most philosophical Doom has ever been is in the unpopular Doom: Annihilation, which had a very explicitly intellectual and serious approach to the source material. The reboot series could have done more to foreshadow or explore its eventual lore earlier on (such as the inherently theistic ramifications and clever inversion of the relationship between the Dark Lord and the Father). Still, the core metaphysics of the franchise gets its most unflinching portrayal here, despite the stupidity of some of the concepts presented--like the idea that the uncaused cause created all things. This idea is only derived from assumptions and outright errors, not from reason; it is impossible for the uncaused cause to have created the laws of logic, the empty space that preceded the universe, or itself. Issues like this, either way, could have been more holistically integrated into the story if the theological, pseudo-theological, and cosmic backstory came to light earlier in the franchise.
Conclusion
The Ancient Gods mostly delivers expanded lore and extreme difficulty, adding another approximately 5-7 hours, depending on how many times one dies, to the reboot story started in 2016 and continued last year. This DLC campaign coupled with the main game are Doom at its most narratively complex. Familiarity with the 2016 game and Doom Eternal helps, but even some who loved those previous games might be overwhelmed by the sheer challenge of the combat in this addition to the Doom mythos. Those who can endure the new enemy buffs, the often confined fighting quarters, and the presence of multiple semi-boss demons have a better chance of seeing how The Ancient Gods is a grand sendoff, for now, to a story far more lore-heavy than the 2016 game ever directly suggested. If anyone is looking for a bloodbath for both the Doomslayer and his foes, this DLC campaign will be the best way to sate that urge so far.
Content:
1. Violence: Lots of blood, severed limbs, exposed bones, and violent physical strikes are part of the regular gameplay.