Super polished great entry. First of all, graphic design is amazing, all looks beatiful and gives retro vibe, especially with the boss with stone hands, it felt kinda nostalgic;) I am amazed how pro ypur entry looks and feel, bloody good job!
I struggled a bit with jumping, it was to fast for me, and because of that I was dying a lot, but i see a lot of games has this kind of jump implemented so i guess its just my personal preference :D If I need to point anything: would be good if you implement some indication after aquiring new skill. I wasn't aware when I got double jump, It took me some time to figure out I got it, and second thing, its good to close boss arena after fight begins, I was able to exploit a bit mr Stone Hands when I went right of the arena. He was just floating above me and I was able to end him quickly;)