The falling leaves and background give me a peaceful feeling that contrasts with the combat system (peacefulness vs. fast-paced action) — I really like that. You have the visuals. The gameplay is there too. I think what Preece said would be very helpful. The basic mechanics are what will make or break your game — focus on them. I struggle with that too, I know how hard it is to find the best values, but it is the core of what you're making. I would add that dashing is OP atm, especially because you can dash indefinitely on walls, which kills the wall jump technique.
Also, I couldn't find it (sorry if there's one), but I think a reset key would help you. I had to close and reopen the application because I kept climbing walls I shouldn't, jumping outside of the game view. I think it's a handy feature, and you can remove it in later stages of development.
In conclusion: really liked it; wanna see more!