I found it really difficult to evade the triangle enemies - their hitbox and timing are more difficult for someone who didn't make the game, and if you're anywhere near them it's hard to dodge out of the way. It took me about ten tries to make it past the second room.
The critical mechanic is interesting! I still found myself sometimes just firing whatever I had because I needed to skedaddle, and moving throws off that tightened critical aim anyway. It makes enough of a difference to be worth lining up, but lining it up takes a lot of concentration with all the factors you need to watch for in any given moment.
One suggestion I'd give is adding some form of negative feedback loop to the game - enemies being added to the room after some are defeated, or keeping high amounts but limiting how many can crowd up on you. Right now, my gameplay focuses almost entirely around quickly downing one enemy, because once you whittle down a room you can easily defeat just 1 of anything.