Really a fun idea that works well in these small puzzles! I played to Stage 6 and died a looooot on my way there ^^
I'd say the hitbox of our character and of the enemies is a bit hard to read sometimes (I lost count of how many times I felt like I could jump above that fire enemy in Stage 2 ^^) but I really dig what's there. I also enjoy the fact that loosing all our lives doesn't send us back to the beginning of the world as it would be quite painful!
I'll be following the development with care, congrats!
(are you on any social networks so that I can follow you there if you happen to post about your games?)