The art was great, especially the lighting and the audio suited the atmosphere, too. I'm always a fan of top down run and gun gameplay, so I really enjoyed this and I loved the level design, with all the secrets.
Lots of people have mentioned the framerate/spongy enemies, so I won't go on about that. It would be good if you made the enemy deaths a little more juicy - a louder sound effect and maybe some sort of explosion that would stand out against the slime puddle they're wading through, maybe?
Super polished and fun to play, especially in the short amount of time you spent on it!