This was amazing.
I loved the chain mechanic, things like that are always so good when properly implemented, and you made it really cool.
Some things I'll say though, I feel like the character could have some invincibility after getting hit, since you could die instantly if you're not careful, especially true in the boss fight, I fell a couple times on top of him and since I couldn't move I just died since I kept touching him.
But despite that, this was really fun! I'd like to see you continue with it and add some more levels!