Your take on the double-jump is really creative! I think the only thing I didn't like was the lack of checkpoints. Respawning at the last upgrade gets kinda tedious when you're trying to figure out a room and get sent four screens back each time you die. Maybe make the little yellow mushroom house in the central area into checkpoint when that room is entered.
Thanks for the feedback.
We just released the first update fixing this (and more) problems.
It will be playable after the Metroidvania Month Game Jam 19 ends.