That was neat! The concept is cool, the mechanics are competent, and the character art is charming. I especially like the final boss design!
Despite the benefits of defeating them, I found myself running past most enemies. The vastly-open level design made most of the game trivially easy in this regard.
I don't know if it's a graphical error on my end, but the camera doesn't align with the pixel grid, creating subpixel renders (look in the middle below the HUD).
There's also an awkward "stretch" effect applied in lines towards the center. I've marked it in red.
All-in-all, good work! Congratulations on the submission!