You should have the platforms to be more forgiving, not everyone is a fan of precision platforming unless the game is centered about it, you can frustate people even though they know how to solve the puzzle, I think the puzzle should come first than precision platformer.
And the rest of the game is pretty good, nice chalck textures and puzzle levels.
And sorry if I sound like a game journalist. Please don't degrade me to that level but anyway the game is pretty good, hope you are doing great, thumbs up!