Pretty cool game. I really liked the palette color that you used, it matched well with the theme and the sprites. Probably was tough to implement the ball`s pyshcys, but it worked fine.
Suggestions for a possibly post-jam version:
* Set the screen a little bit smaller, at least on my computer the screen was way too big.
* Make the background more dynamic, maybe a commet passing by would be enough.
Congratulations for your game, you shall be proud of it.