Yooo this is sick!! Very cool! Very much nailed the retro vibe with the music and graphics, everything.
Mouse sensitivity was INSANELY high at first, I managed to get it down to something reasonable but it was a bit of back and forth between the main menu. I would just add the slider to the pause menu without backing out of the game since it's easier to test. That's a small thing though.
Otherwise the controls felt smooth! I really liked the way you climb ledges, nice touch. Although there were some platforms it looked like you could climb but couldn't? Some of the rebar was angled weird... I spent a good while in a pit with a few pieces of rebar trying to make it out but I don't think it was possible.
Sometimes the map was hard to see, in the opening I spent like 5 minutes trying to climb the pipes in the first room before realizing there was a hallway to walk down lol, it just blended in. Everything also looked kinda samey, it was very easy to lose all sense of direction. I walked into a room and couldn't tell if it was the room I started from or not because it looked pretty similar, although I think it had a platform that wasn't in the starting room and I was gaslighting myself lolol.
I think the enemies could use some feedback, when I started shooting them I couldn't tell if I was actually hitting them and they had so much health I wasn't sure if they could even be damaged until I blew one up. The grunt the main character makes is really funny though lol, def contributes to the retro mood I think you were going for.
The game isn't very forgiving, none of the enemies drop health and I couldn't find any way to heal or recover shield or anything, it's a bit discouraging. After a point I gave up on fighting entirely and just ran everywhere. I feel like maybe the shield should regenerate over time or maybe there should be more save points if there are no health drops... Doom isn't usually my kind of game though so maybe I'm just bad 😅
In the end I only got the double jump and gun, but I hope you keep working on this!