Played some more, I'm some way into level 3 on Hurt Me Plenty. Still on a bloody controller, a travesty but I really like sitting farther from the screen and haven't used kb&m for ages as I don't really play shooters
Really having fun so far, I get the complaints how it has changed the formula (it undoubtedly has) and it's not really (that much of) a mindless shooter anymore. It does rely on weak points too much on certain enemies as well, which can be annoying when it requires so much speed and managing.
Still, it's probably the most fun shooter experience I've had in YEARS so far. The combat flows great and I really dig the mechanics of it all, it feels wonderfully arcade and satisfying to pull off.
The entire game is arcade and ridiculous, and I love it. The level design, collectibles, stupid platforming and mental combat. It doesn't take itself seriously.
You could indeed say it's not really Doom anymore and you wouldn't be wrong but whatever. All I know is that the first Slayer Gate I did, which is in level 2, gave me more of an adrenaline rush than endgame stuff in 2016 and I was actively using more of my stuff.