Very cool esthetics in this game! Sadly it suffers from:
1. No checkpoints (as far as I played)
2. No grace period after leaving a platform, where as a platformer should allow the player to jump maybe 0.1s after losing contact with ground.
3. No comeback mechanism if I missed 1 single jump
4. The jump curve felt very fast and punishing, especially as it seems to be the main mechanism of the game.
The idea, graphics and audio were all nice, so if you get into the habit of implementing grace period and other platformer necessities you will become a great game designer!