This was interesting to play! At first I couldn't understand where to go or what to do, and I realised that jumping reduces health? However once I figured out where I needed to go, the boss fight was really good! The fight is fun, the boss has varying attacks and it overall looks pretty good too!!
I also need to credit you guys for making the controls fun to use, it helps improve the polish overall of the game.
I'd suggest that you add more direction and perhaps flesh out the story so that the player can understand exactly what they need to do, because you guys have clearly done a really good job on the main fight, its just getting to it that's the problem!
This is a minor bug, but during the platformer phase, you can let Health reach 0 and nothing happens? This is minor though and didn't affect gameplay too much!
Great job overall!