Alright, so now that I've gone through it, beginning to end, I have to say... it was rather tedious at times. I started on Nightmare, went down to Ultra-Violence and halfway through the game picked Hurt Me Plenty because some of the fights started to become a literal nightmare to get through. There were some arenas were I kept on dying and I did appreciate the challenge at first, but it got ridiculous to the point where you had to perfectly position, do the kill combos and use the right weapons in order to survive. It's definitely an interesting take with the expanded glory kills, but the focus of the game has shifted way too much on the resource management and playing it a certain way. And I absolutely hate that you can't just shoot enemies to death - you can, but you can't survive without those resources they drop otherwise.
I thought the level design was alright for most of the part, but wasn't a fan of the platforming, especially in the later levels. The jumping bits in the alien world were just atrocious - and this really made me appreciate Xen even more. Other than that, environments were super well done with a lot more variety than 2016 and I liked the expanded lore as well. I don't normally read these collected notes in games, but I enjoyed these for a change. I also didn't mind the cutscenes. They were pretty brief and longest were probably in the beginning. The music and overall sound are pretty much flawless.
Overall, it's an alright game, with some definitely awesome moments, but if you're expecting a classic fps experience then you're going to be disappointed. That's why I recommend you play DUSK instead.