thoughts on mechanics: interesting platforming concept with environment and player body manipulation. I wonder what your next game would be like.
difficulty: it isn't for the casual player but not nor the hardcore either
difficulty suggestion: make an extra level update and make it near as hard as possible for hardcore players if you want.
Next game suggestion: If you have (a "Steam" account)/(access to Youtube) & likeness for difficulty in mechanics and environment go and look for Hollow Knight and watch a video of (Hollow Knight "White Palace" or play the game I bet you'll like how the devs made the environment.