Pretty sweet that you got a full cutscene in at the start, and after completing the first objective. I couldn't progress past that first objective since I started getting attacked during the cutscene and then died while unable to move my character lol. It was actually super funny, since it looks like there was about to be some sweet exposition, and the very moment the reveal was about to take place, I died and the menu popped up. Maybe the game ended there anyway because I later tried skipping that cutscene and it just took me to the in-game menu, still unable to move my cursor - but holding LMB and tabbing across the buttons to 'play' it then took me back to the opener, so I'm guessing that was the end.
I like the look of the GoW-like ADS mechanic, although I didn't get to use it since every encounter happened at pretty close range and there didn't appear to be any improvements to gunfire when aiming down sights; also anything that made me feel like I was slowing my movement speed, especially during the flag-plant objective, was cast aside so I could try to escape the mobs that were coming from all sides (pretty tough encounter if you're trying to avoid taking damage). A little bit of lighting could help particularly in the room that sort of loops back on itself, although I get this isn't supposed to be 'hospitable' as much as an underground/maybe fleshy membranous tunnel where lights wouldn't make a lot of sense... A little bit of randomization and/or some variants for the weapon sfx would go a long way, imo. Also those mob attack sounds, they remind me of demons/bull demons/pinkies from Doom 2, which I thought was a good choice for their mouthy design. I liked the enemy models, and the mood shift when the player character is revealed in the opener is pretty sweet with the camera and the music. Oh yeah, and the cel shading - I feel like I don't get to see this as often as I like, I'm not sure how easy it is to implement as a non-programmer/artist but it looked good! Because of the hunky player model and the way the ADS looked, ...I felt like having a combat roll or something and a grenade would fit right in. And then maybe I could finally watch that closing cinematic! Nice work!