I enjoyed this. It took me a while to figure out the controls, but I eventually figured out how to damage enemies. I think it's because the brush isn't equipped by default and there's no swing animation. I got into the flow of damaging enemies and upgrading my powers, which was fun.
I think having an easy way to heal would be nice. I couldn't find one during my playthrough of it. And having the player's movement speed being below the enemy's speed made it a bit difficult at times, particularly when you're running from enemies while trying to damage them.
This is a good concept and really impressive for a game jam.