I like what there is so far, but I feel like the wall-jump controls are kinda clunky, I'm struggling to get onto the next wall quickly and I would get stuck on the wall that has a gap in it. I'd also appreciate the game window just being smaller and not having to resize my browser.
Maybe you could find a good pixel font for the instructions, and have the game music not restart when I die? It's these little things that can really make the aesthetic of the game feel complete.