This is interesting! I like it and I have one main critique. I don't know if it was intentional or not, but the enemies blend into the environments perfectly. It'd help if something about their sprites stuck out so you can see them from across the room. That, and I think the HUD elements could be more saturated, so they can pop off the screen better. I don't know if that's because of limitations with the hardware, I don't know how you made this, lol.