Hey
This is very cool idea and you should definitely make another update to this. I struggled to play this in the browser, I felt like there were times where the gun wouldn't shoot or do anything. Sometimes, I couldn't even rotate with mouse.
I am hoping that it is just the browser which is causing all of this issues (most likely). Because of this I couldn't really try any of the core gameplay as I would die before that. A little modification + music would elevate the current gameplay.
Good luck :)