Beautiful game!
The platforming was just right, with some especially tricky jumps in the slanted roof section, since they require Mumei to be standing exactly at the top, where she won't slide down. Took me a few tries to get those jumps right and make the way back home.
Mumei's sprite is super cute and the intro/ending sequences were a really nice touch. However, the star of the game is the BGM. The way the music changes as you progress in the game is a great addition to the storytelling and ambience! Great work!
Some improvement suggestions:
- Making the "safe" area on top of the slanted roofs a bit larger and blocking off wrong paths on the way back home would help a lot to reduce player frustration. XD