Okay, I beat it this morning. Took 16 hours total.
I really enjoyed it, but like others have mentioned, it definitely felt rough in places. I know people mentioned the possibility of a different internal team, if that's not the case, I think it could've just been rushed. There feels like a lack of animation with certain in-game NPCs, I've also seen the placed in the wrong areas so they're typing on air, lol. Bunch of invisible walls and other things that feel like they were done quickly to just make ends meet, etc. The game's still a lot of fun, the combat and the mechanics are great. If you liked the recent DOOM games, you'll likely enjoy this one, I just can't say how much.
For me, I think by the end of it I'm still thinking DOOM 2016 > DOOM Eternal > DOOM The Dark Ages.
The worst thing about this game IMO, is that for someone like me there's really nothing left for me to do. I beat the game, and that's that. If I cared to play through it on a harder difficulty, find all the collectables, etc. it'd be a different situation. But for me, I beat it, and that's that. One of my favorite things about 2016 was not just the tone feeling more like OG DOOM (because the story and lore didn't go all nanners yet), but the fact that it came with a lot of content. So once you were done, there was multiplayer, there was Snap Map, etc. With Eternal there was still some stuff there, but it much less than 2016 had. Now, with The Dark Ages, you have even less as there's just the campaign and secrets to find.
I'm not dogging on the game, I definitely had fun. But now that it's done, I honestly may just uninstall and revisit when the DLC eventually comes out.