Thank you for the comment! I just noticed the Skeletons don't shoot, although they're supposed to. I'll work on a fix.
And I was definitely thinking of adding a shop later on, and better enemy mechanics, maybe health, etc. But I won't be adding anything like that for a while. I have another project that I'm going to be working on, another top down pixel-art game, but this time a RPG with a story, NPC's, etc. I'll use skills I learn developing this new project to add onto this one later on!
Again thank you! And I will definitely try out your game!