Great game! The graphics are really cute, the music is a bit short but fitting, I really enjoyed the concept and the general feeling of the game ^^. Each world have their own identity, there are several levels, and you even added a couple of NPCs, that's a lot of polish for a 7-games jam ^^!
I just have a couple of nitpicks ^^':
- I would have loved to have a way to know in advance the layout of the different universes, like an outline in the background or something. I died a cople of times because I teleported and fell into a hole xD.
- The ice physics are a nice touch, but the fact that the character is affected by the ice even airborne is really weird and threw me off-guard a couple of times xD
- On Windows, the game closes after each death. On WebGL, the levels freezes and usually restarts. But I died a couple of times on level 6 and the game just froze ^^'. I'll try to finish the game another time, because right now, I'm a bit mad to restart the first 5 levels xD. A level selection would be great ^^'.
Other than that, the game is really solid and the idea is perfectly in the theme. Congratulations, you did an amazing job =)!