I really love the art and the character animations for this game! But I think it would've been better if you let the character climb down as well as up, to dodge projectiles better. I get to a point where there's 4 enemies shooting fireballs at me simultaneously, and I'd love to have a little more freedom to move around instead of taking them all at once.
Having some music and SFX would really add to the experience, as well. But you definitely have a great idea coming along, good work!