I love this, the art is just fantastic, and the idea is great (even if i did see something similar in LD a year or 2 ago ;D).
My only criticism is the amount that you slide after hitting something. Maybe its just me whining about being bad and not being able to judge the slide well, but i feel that in a platformer like this, accuracy is pretty key. It wouldn't exactly be hard to implement anyway, i'm pretty sure this was made in Unity, and it would just take adding a physics material to the floors with higher friction.
Maybe play around with it for next time, see if it makes it more accurate, or maybe just see if it ends up making it too easy?
Anyway, great game :)