Very nice and enjoyable to play !
Just few things :
- when you die you should restart with all your heart. Else it immediately turns into a non-damage hardcore mode.
-at the boss, if you are hit by a rock, you can't jump or escape until then end of invulnerability time, which means that if you are hit, you're dead already.
Great game anyways, the controls are responsive, you could put some harder levels