Interesting play style. I can deal with the random rooms, random weapons, that thing was fine. It does lead to some rooms that pretty much are guaranteed to rip your health to shreds, especially when you have too many enemies on screen and a weak weapon. Although I think the way that that works against you is more a process of hit confirmation. Simply put, you can take hits a lot faster than enemies can. No matter what you shoot an enemy with, it takes about a second for them to register the next hit from whatever gun you're firing. Meanwhile your character can take damage at least twice within a single second, meaning that you are already bound by increasing damage and no health refills but then on top of that your character is designed to soak up damage like a magnetic sponge.
The thing is... the difficulty altogether makes it awkward. Despite the randomness, if I got to a high number of rooms, I should still feel like there was a lot of skill involved. As if it was an accomplishment. Instead, all I really feel is lucky, and like I occupied my time but that I really didn't achieve much of anything. That's where your game loses stars more than anything else.
I would say, deal with the hit confirmation on the player character and that would be about it. Everything else seemed alright.