Doom Eternal demands you to learn its mechanics or die
Doom Eternal initially was a turn off for me, after beating Doom 2016 over and over. Everything is so different... ammo pickups are neon pink and green, guns are floating neon items that you pick up just by running over with no cool animation, ammo is as scarce as in a horror game, and you're thrown in this mess of not knowing what's happening except "I must kill".
However after playing a few hours and getting the hang of the combat loop, as well as getting much needed upgrades and some verrrrryyyy interesting codex entries, everything started to click. The story felt more cohesive and while there is a bit missing in the gap between 2016 and Eternal, much of it is filled in and then some. You get used to the recharging chainsaw, so ammo is never an issue, and while I still miss the realistic weapon pickups from 2016, I understand why they changed it.
Yes, there are some definite differences between Eternal and 2016, but nearly all of them are for the better. Combat is even more visceral, and while it may at first feel the game is forcing you into a certain play style, it's ACTUALLY giving you more control on how to manage resources. You have to play smarter, but you can also remedy any situation far easier than in 2016. Need armor? Cook em. Health? Stab em. Ammo? Saw em. It's so straight forward but very satisfying at the same time. And after experimenting a bit with weapon loadouts, you DO NOT have to use sticky bombs or zoomed rifle shots to disable demon weak points. It is preferable because it's much faster, but I was able to disable their points with different weapons or completely ignore them entirely, by overwhelming them with firepower.
I will say (no spoilers) they really fleshed out the lore of Doom, and made it far more interesting IMHO. Much of it is implied and hidden in the codex entries, but it actually makes the occurrences of Doom 2016 much bigger and interesting. I thought they did an amazing job with the story/lore.
Of course, this wouldn't be a Doom review without also mentioning Mick Gordon's stunning soundtrack once again, that makes you miss shots due to headbanging. It is a simply ear-gasmic experience that perfectly complements the ripping and tearing you do in Doom Eternal. The joke about Mick Gordon's soundtrack coming with a game is fitting, as I see both the soundtrack and the game as some of the best media to come out in recent months (at least for me).
I haven't even tried Battlemode but I can say as a RAVING fan of 2016, that this game is 100% worth it even at full price just for the campaign. It took me 20 hours to beat, without even hunting for every single collectible. The whole thing was a roller coaster ride of flying gore, pounding metal and chunky guns, but with a surprising amount of twists, environments, and experiences. They knocked it out of the park with this game, with the sheer amount of places you get to visit (the sentinel cities are soooo cool, with a weird nostalgic atmosphere to them). Also from a technical standpoint it runs very smoothly, and I've had very few problems with it on PC. It's an extremely well polished game!
Overall Doom Eternal is simply everything I dreamed it would be, which is really saying something these days. ID Software should be PROUD of this masterpiece and I can't thank them enough for continuing on this series.