At the end of Doom Eternal, I was left with a bit of disappointment. Too many things were forced into the game and it got tiresome towards the end. New enemies were uninteresting and slowed the pace down some, too much platforming, and the difficulty was all over the place no matter what difficulty setting you were on. The Ancient Gods, sadly, exacerbates this by adding a new enemy that, once again, slows the pace down and is just an excuse to use a certain weapon mod. There are no new weapons, just three newish levels. I say newish as the third level - The Holt - is a recycled Urdak level. It's boring and uninteresting, yet the first level, UAC Atlantic, is just a giant science center in the ocean. The Swamps, the second level, was the most interesting of the three, but they aren't amazing overall.
The story takes place right after the ending of Eternal with Doomguy trying to kill the one true Seraphim God to end all demons. It's mostly just dialog over intercom here and there and just barely advances the already silly Doom Eternal story. Outside of a few codex pages, there's not much else to the story here. In fact, there are even fewer secrets to find. Just 1ups, BFG ammo, codex pages, and there are six Gore Nests and three Slayer Gates. The Gates will give you an extra perk that has been added, which aren't very useful, and the Gore Nests reward new Slayer Skins. That's pretty much it for secrets, but the levels are very long and incredibly difficult. Combat arenas are tougher and longer and I died numerous times in each level even on the lowest difficulty. This is my biggest issue with Doom Eternal. Doom 2016's areas felt hand-tailored, but Eternal's feel randomized. Even the final boss is insanely difficult with too much jumping and worrying about obstacles rather than just shooting.
The Ancient Gods feels mostly like stuff from the cutting room floor rather than an actual expansion. There's almost nothing new here outside of 2.5 new levels and a few perks and two irritating enemies. Yes, like Maurader and Maykyr Drone, these enemies just slow the pace down. We get another Maykr Drone that has a shield and is only vulnerable when it's down, and then there are the Spirits. These possess demons and make them stronger and the only way to kill them is to use the Microwave Beam or kill all the enemies in the area so it disappears. Super annoying, not any fun at all, and just slows things down. I would have liked to see a new weapon or a new actual demon.
Overall, The Ancient Gods are still fast-paced and fun Eternal combat, but it's just not enough new to be considered anything more than some lost levels. Fewer secrets, new annoying enemies, insanely pumped up the difficulty, longer and less interesting levels, and only three new perks. It's still plenty of fun and if you finished Eternal early on then this will give you a few hours of mayhem to get another taste, but it's nothing to write home about.