Really fun! I like how timely use of getting new upgrades can heal you (if indeed that was intended. If not, it's a bug that allows for major exploits as once I learned that, I was able to pull off some major progress each death, with the first two maps being cleared sub 1 min.) I'm a sucked for mushrooms and really enjoyed the game. Good use of the theme.
2 bugs, though, to bring to your attention: first, if you die while using the dash attack, sometimes it causes your avatar to fly across the map before collapsing. And 2, sometimes the dash attack can land you stuck in rocks, and there's not much you can do beyond waiting to die.