Overall I enjoyed playing the game. It was fun. The few things I would improve on are: (unless I missed it) a way to heal as I personally died super easy even without getting hit *a lot* and going from room to room without a way to gain hp made it hard. The first gun you get feels weird to shoot, sometimes it shoots and sometimes it didn't and I don't know why.
Had a bug when I picked up a gun it crashed the game, only happened once so far but didn't give an error and I haven't tried reproducing the bug so might've been a once off.
Nice job though! :D Did you do all the pixel art yourself? I assume so, but either way well done ^.^