I have a few suggestions!
First off, the music crackles in my headset, this might be just me but no other game does this so maybe you could fix it?
Second, when you get hit you should get knocked back or something similar, at the moment there is no reaction from the character and so it is often surprising when you die. Similarly enemies also don't
Third, it's not entirely clear what is a wall and what is not a wall, this could just be me but I found myself confused at times as to where I was allowed to walk, this could be fixed with more clear differences between background layers and foreground layers.
Fourth, the main interaction with enemies is inherently boring, you kite back and shoot kite back and shoot. There is no dodging or anything similar, you can't even dodge the wizard magic balls, they just home in and hit you.
Well, I've gone and written this all out, but I don't want to give the impression that I don't like the game or that I'm trying to be mean. I just saw that you wanted suggestions on the forum and I decided to come and comment what I thought could be improved :) I also don't think it's a bad game, it's got an interesting premise, cute art, and I think the song would be good if it weren't crackling!