I really like this game, the idea is cool, the choice of music and font is great. This really shows how good looking you can make a game with simple shapes, a good color scheme and post processing effects.
The controls: The controls are great, especially the double jump feels perfect, but something i noticed is, that when you toujch the wall on the side, your jump is reset. I don't know if that is intentional, but i liked it and it is only helpful.
The levels: I like how you slowly build up the levels, and i like the difficulty, BUT i had to stop playing this game because some of the levels are just unfair. In the first level with enemies, the enemy seems impossible to dodge and i had to skip the level. The lava part of the laser level is also impossible, cause if you need to wait for the laser to disappear, the lava is above the platforms and you can't use them anymore. And at some point i thought at the beginning of a level "how is this even possible" and stopped playing. Difficult levels are fine, but not unfair ones.
Overall, i really like this game and i will give it a good rating, but it will get a few minus points in fun and game design because of the unfairness. Maybe you could change that stuff after the jam is over.
I hope my feedback helped you and it would be nice if you could check out my submission too. Thanks :)