The idea is very interesting. Using the health as a timer and give different skills to the player based on that.
The art is also very good, but as other comments say, it's a bit difficult to see what is interactive or when the gates are open or not.
Maybe another detail could be add some marks in the bottom bar to make more clear when the character can push a box or have the double jump. The detail of the head being smaller over time is cool, but sometimes I didn't know when I was able to use the double jump.