Nice! It's a unique idea for a puzzle-platformer that could actually become very interesting!
There are just three minor problems that can easily (I hope) be fixed.

• One is the restart button. It doesn't exist. I used the gravity option in the last level, fell through a hole in the ceiling and kept falling for eternity.
• Second, there are only four levels, three of which are just there to teach you the mechanics.
  There's only one real level. While this could be considered thematic, I believe you should add a couple more levels, each more challenging than the last. The game would feel complete then, instead of leaving the player wanting for more. (I certainly did!)

• Lastly, the character sometimes glitches through the ground. It's not enough for them to fall through it, but it's definitely noticeable. I think this happens more when you flip gravity, but I'm not really sure, haven't tested it that much. It probably has something to do with the height you're falling from, I don't know. You get stuck and have to glitch your way out of there, is what I'm trying (and failing) to say.

In any case, if you don't have any other projects currently, give this a shot! It's a really cool idea, and if you invest some more time into it, it could really become a great game!

Really cute! But so short! Would have loved to have a level where my choice actually mattered.