Woah, this game has an awesome aesthetic! Love the black and white, had cool effects like the screentone shader, the UI was cool (although the resolution looks a bit crunchy)
I think maybe the shooting could have used some feedback like a sound effect for gunfire or muzzle flash or something because I couldn't really tell if I was firing at first... Also it looks like the gameover screen didn't scale quite right, on fullscreen its a red box that doesn't fill the screen, dunno if that's intentional. It has a cool animation though I'll say, and the start menu was sleek too!
The monsters are also very brutal in difficulty... in all of these cramped corridors it can be really difficult to leave because they overwhelm you very quickly and if they touch you you're basically dead immediately. Although I will admit by the end I was just running past everyone and jumping over them like a speedrunner lol.
It's unfortunate it has nothing at all to do with the theme... I don't know the circumstances of why starting late means it didn't get incorporated, but maybe you could have shoehorned a plot of having to kill all these guys to deliver a present to someone?
It's okay though, you still made something awesome!