Wow this is a pretty polished game! Congratulations on your achievement. I was really impressed by visuals and all the extra attention to details like the intro sequence (though like others I thought it was a lot of text to read).
I'm not opposed to difficult games (in fact I quite like them), but there were a couple things that made the difficulty less enjoyable for me. First, I wasn't comfortable with the controls. As others mentioned, controller support would help, or even just another keyboard option (I personally find wasd+space+shift very awkward to handle. It's a lot for one hand; I prefer zx+arrows). I agree that the wall jump could be refined, but really this wasn't a big issue for me. Second, there's the constant risk of falling to your death. That's not bad in and of itself, but combine that with a lot of knockback on small platforms, a very quick respawn that makes it easy to immediately fall off a platform, and ambiguity about where the death spots are and where there is a platform below, and it makes for a somewhat punishing platforming experience. I think that with a bit more attention to the controls (and options for a variety of player preferences), this could be a really great.