UPDATE 11/25/20: With the addition of The Ancient Gods Part 1, this game is cemented as the Game of the Year

So after anticipating this release since June of 2018, I spent the weekend knee-deep in the DOOM and came out of it extremely pleased.....and I was expecting a lot.

Eternal is essentially DOOM 2016 x3, in terms of speed, difficulty, fun and tactics you can (and need to) use. If you have been following the development of Eternal, you will know that you cannot play Eternal the same way you can DOOM 2016. DO NOT go into this expecting it to just be DOOM 2016 but with new monsters and some new guns, like DOOM II was to DOOM I.

The mechanics have been specifically designed and implemented to teach you the best way to play this game. You cannot run around with the super shotgun expecting to be able to waltz through everyone (I bet someone will do it eventually, but it's not suppose to be easy or fun like that). Use the chainsaw, use the flame, use the meathook, use the movement abilities, the real Doom Dance.

It will take a bit of getting used to; even I thought it was a bet overwhelming at first. I started off in Ultra-Violence difficulty, but the game very quickly teaches you how to use everything, in a fun manner. The game expects you to adapt based on failures - even when I hit a particularly difficult secret encounter, which is essentially a timed fight with some enemies, I constantly was looking for the best way to win.

With that said, there is no shame in doing it on lower difficulties if needed. "DOOM is suppose to make you feel unstoppable"

LORE/STORY/WRITING: If you choose to dig into it, the lore aspect of the game is very good. Many arguments within the doom community now resolved due to info from this game. It's presented mostly in a very concise manner, most of the deep stuff is find-able logs that you can ignore if you don't have interest. Cutscenes are short and skippable if wanted. DOOM Slayer continues to be the most fleshed out and expressive silent character in a video game. You can find a lot of humor in some interactions.

There is some disconnect between where Eternal starts and 2016 ends, but a lot of it is explained in aforementioned Codex's (involving Earth's story), and the DLC is campaign additions that are going to flesh out pre-Eternal (Slayer's story from 2016 to Eternal).

TECHNICAL: Pretty sure this is one of the most optimized games I've ever played. I got a 2070 Super to run it, but I'm pretty sure my 1060 6Gb would have had no problem keeping a constant 144 FPS on decent settings. Even at high settings, it uses less CPU and GPU power than games that are 10 years older. idTech 7 is great. Also, if you have this game on an SSD, loading times basically don't exist.

SOUND/MUSIC: Mick Gordon. That is all. All other sounds in-game (guns, ambient, dialogue) play very well, with only minor noticeable glitches occasionally.

ART/ENVIRONMENT: Outstanding. Detail level is insane. Environments are awesome. DOOM 2016 got a little bland, this game does not. They were not kidding when they said you would see more variety in first 3 levels of Eternal, than all of 2016.

BUGS: Mostly minor. Only one I really saw was lost souls getting stuck in floors, but it never stopped progression. Apparently some demons would leave areas, then come back. Hopefully fixable stuff.

Common "Criticisms" -

"There is no ammo" - There are walking ammo packs everywhere. Walk up to them and press [Chainsaw]. Late-game perks allow additional ammo and ways to get it.
"There is too much parkour" - eventless hallways are boring, also, DOOM II Map The Chasm
"Why isn't this like 2016" - It is, except the devs realized that running around with one weapon and not being punished for it is not fun to watch or play, so they changed it.
"It's too hard" - see aforementioned Any Difficulty. You will have to think and be a tactician at higher levels - essentially, git gud.

OVERALL: 9.5/10. Would DOOM Again.