Liked: The platforming is solid, the story is engaging, the art work is cool. I loved the background clouds, they are so fun to look at.
Could improve: I know the main mechanic is you can't jump while on the ground but after some time it gets a bit annoying especially when platformers have ingrained the knowledge of jumping when on the ground into you. It can easily be replaced by something else and I think your story and level design takes care of the theme already.
Additional Comments: I'm sorry if I come across as harsh in the previous section but as I said the appeal of your game comes from the visual effects and the story; the platforming is just a means to reach it. It's an amazing work you've put out. Great job.