Interesting and definitely tough game! I think the art and music is solid and fits the game, and the gameplay works well for a hard platformer like this. The double jump mechanic is interesting when combined with the fact that you regain your double jump from touching walls; I guess I find the mechanic tough to master for sure. Maybe some kind of indicator that your double jump is replenished would help, because sometimes I feel like I didn't regain my double jump.
The jumping velocity also felt a bit strange; holding down jump makes you jump higher which is pretty normal, but the stretching of the character made it harder to know if I was jumping the right height when platforming. I think if the double jump mechanics were polished a bit more to feel more consistent in terms of height and regaining your jump, this would be a super fun tough/rage platformer! In either case, well done on the submission!