Very thoughtfully made game. Very polished. Feels great and challenging. Great job. 

Thank you for such a fun game!
The graphics were super cute.

A key that big would definitely be heavy!
But since the character throws it pretty far, I couldn't help thinking, "Wait, can you actually lift this thing?!" lol
One small thing: the high-pitched sound at the end of a stage caught me off guard because it was a bit loud/sudden.
I think a slightly softer sound effect would make the experience even better!