Nice game feel!
I didn't quite understand the main mechanic. I think Q inhales and E exhales, and having a balanced yellow bar is required for casting spells. However I'm not sure how the healing works, it felt like I was randomly healing when pressing Q or E close to enemies.
I think a tutorial, even in text, would have helped greatly!
Also the levels were a bit too big, for the first 2 levels I completed the objectives at the very beginning, and then had to walk all the way to the end to move to the next level.
Overall, good presentation, nice game feel, good to fight many enemies at once and have a bit of bullet hell fun.