Just as a quick warning, there might be some spoilers in here for some stuff. I'm going to try to keep major spoilers and bosses to a minimum, but there is some mid game stuff I wanna talk about so if you plan to play or are currently playing Eternal and don't wanna be spoiled I guess don't read this?
Also this isn't really going to be a proper review or anything. This is the 3 AM ramblings of an idiot who can't sleep.

With that out of the way, holy shit I love Doom Eternal. Big shocker I know. I may not be good at the game but mmm its so f u n. I love it. I have very few complaints with the game, and most of the ones I do have are mostly because of my own incompetence rather than the games. E x c e p t one. But I'll get to it later.

Doom Eternal plays similar to Doom 2016, but not quite the same. The levels aren't nearly as abundant with ammo and armor as 2016 was, but the game makes up for it by giving you new ways to get what you need without just handing it to you. I don't really know how I feel about some of the new mechanics. On one hand the chainsaw being more useful is nice and it's now not really limited to being the "get out of jail by chainsawing a baron in half card." Because the levels have very few ammo pickups and the amount of ammo you can have is way more limited than it was in Doom 2016. So you pretty much always have to chainsaw something, and the game usually keeps fodder enemies like the unwilling spawning in the levels as you fight. Your chainsaw always refills to one charge if you run out as well.
But on the other hand, the ammo limitation is kind of annoying. Maxed out on ammo upgrades you can only hold 24 shotgun shells. Thats like barely over Doom 2016's second ammo upgrade. I get the point though, it's to encourage you to use other weapons and not rely solely on the shotgun or super shotgun. Problem is by the end of the game you can literally do that no problem. I rarely touched anything but the shotgun and plasma rifle near the end. Balista? Never heard of her. I used the rocket launcher more in Doom 2016 then I ever did in Eternal. I only started using the rocket launcher by the second to last boss. But that's probably more an issue with me than it is the game. I have tunnel vision like a motherfucker.

Additionally the game tries really hard to incentivize you to actually use the chainsaw and not have it be the dedicated big guy killer, but then turns around and gives you a new get out of jail free card weapon towards the end. The Crucible can pretty much one shot anything barring like one whole enemy. And unlike the chainsaw where it takes more or less charges to kill different enemies, I'm almost certain everything takes one Crucible charge to kill. To be fair until the very final boss the game almost never ever gives you any charges for the thing. But given that once you really need it the game is giving you replenishing pickups for the things charges that really doesn't matter. Especially because the most difficult enemy I've fought is the only one you can't kill with the Crucible at all, so who even cares.

Also I got sidetracked, the game also gives you the flame belch to get ammo. Use it. Don't forget it is a thing that exists like I did. I went through a large majority of the game without touching it. I am a dumb. Don't be like kit.

Pretty much, be ready to adapt to Eternal's mechanics or it's gonna take a second to really get used to the game. I went in ready to play like I do in Doom 2016, and while I didn't completely get my ass handed to me, I still struggled at some parts.

I really like the new movement mechanics though, dashing is very fun for some reason to me and once I finally got the hang of the super shotguns meathook that was especially fun. It took me until the second to last boss where it was literally mandatory to finally start using it though. But we live and learn kids.
Climbing is also pretty fun. Although climbable walls could stand to be a b i t more noticeable in some areas. I died in one area to a timed sequence because I didn't find the wall to climb until the very last minute. I've also seen people mentioning climbing being a bit janky and not registering you actually attaching to the wall, but I've never had that problem. Most of the times I fell off a wall or didn't stick to it were because my jump or dash was short or because I dashed into it and tried to jump or hit another button and detached.
The new mobility makes platforming pretty fun in my opinion, or maybe it was just because I could grab the In-flight mobility rune right from the start as my first rune. I remember The Argent Tower level from Doom 2016 being the absolute bane of my existence, but I had a lot of fun climbing and platforming in Eternal.

I really like blood punch as well. No reason. Blood punch is just very satisfying and very fun.
I don't have much else to say for new abilities or mechanics. Demon weakpoints are a thing. I don't really care much.

I'm kind of bummed you almost never get any powerups though. Beserk is the fucking best and you literally only get it like one whole time in the game. I think you get quad damage and haste a whole like twice each.
Haste is also kind of a bad mix with the new mobility though. In Doom 2016 Haste was fine and it sped you up but didnt make you too fast. In Eternal though Haste essentially makes you go the speed of light it feels like and it becomes a challenge of not running or dashing into walls. It also just makes hitting demons harder because standing still in Doom is a death wish.

I love the lore though. Like in Doom 2016 I went out of my way to find every codex entry that I could in Eternal. I was super excited to play new levels, one to continue the game in general, but also to get more lore entries. Story really isn't super important to Doom, but screw it I like reading and lore is neat. I especially wanted to finally fucking know if I was correct or incorrect about The Slayer being Doomguy because so many people were like "No he's nooot" but you know who was right this whole time? I was.

The story is admittedly kind of a mess a little though. I have no clue what's even going on with Samuel Hayden anymore. He knows way more than he should, or could and I think it's implied he's not supposed to be who he says he is. But that somewhat contradicts what he says and does in Doom 2016, so like fuck if I know what's going on at all. I audibly at one point said "How the fuck does he know any of this?" When I was having exposition thrown at me about a place Hayden could have n e v e r been to.
I do kind of find it funny though that it takes about 5 whole minutes of Hayden being back before he's already sick of the Slayers shit again. You'd think from dealing with him first hand before Hayden would realize telling the Slayer he can't do something is literally not going to stop him from doing that exact thing.
Thats actually a lot of the games interactions though. Character tells you that you can't do x thing or take x object. You immediately do it anyway.

Okay, thats basically all I have to say about that. I have little to no complaints on the game. Besides this one fucking thing. The Marauder. I hate the Marauders so much, I feel genuine rage when I realize I have to fight one.
They are by far the most difficult enemies in the game, and they're the second super heavy type you encounter. They make the ones you encounter after them look like a fucking joke. It's not even a case of them being genuinely difficult because either the player is bad or something like that. They're difficult because they completely disrupt the combat flow and force you to focus solely on them.
You cannot hit the Marauder unless you managed to see them for like the half a second their eyes flash green to attack you. And sometimes they just don't stagger. Or their eyes flash, you shoot and the cheating bitch pulls up his shield. Any other time they will block your attacks. Including the fucking BFG. I managed to one shot a Marauder with it once out of pure ass dumb luck. That was the luckiest I ever was. You also can't kill them with the Crucible at all. On top of that they can spawn dogs. Sometimes even just on top of eachother. There's been plenty of times I've killed his damn dog just for him to immediately send another one after my ass. The Marauders consistently and mercilessly impede my progress. I hate them so much. Part of it's me being bad, but for a little bit I was actually getting better at fighting them and then suddenly it went back to me getting my ass handed to me for like 3 hours straight.
They're supposed to be hard enemies but like, they way you are supposed to fight them, is not at all the way you fight in Doom. You're not really waiting for openings or trying to stay at a specific range to an enemy. You're ripping and tearing your way through hordes of demons relentlessly without pause. The Marauder grinds the pace to a halt when he shows up.

I feel like he'd work better as a one time boss, or just get rid of his fucking dog. I hate that dog so much, I understand the Marauder mostly at this point. Except for what triggers thag fucking dog. Is it being too close? Being too far? Fuck if I know.

But other than the Marauder making me want to commit real felonies against people in my general vicinity, I absolutely love Doom Eternal and I feel like I'm going to play it to the point I know the levels and enemy spawns like the back of my hand like I did in Doom 2016.
But anyway, thats about all I have to say. It's like 5 AM almost and I'm tired.