The visuals are alright, I like the boss design (very detailed for a pixel art game) and soundtrack (very relaxing for menu music). The 8bit theme really reminds me of old NDS games. I do have some problems I wanted to address:
When you switch gravity there's no clear direction on where you're going or where you're landing. Additionally the floating hands are randomly moving thus means you get hit multiple times before you hit the ceiling or ground. Some deaths happen without your control basically.
Consider maybe disabling the collision of the hands when the player is airborne?
Apart from that I enjoyed it! I gave it a few tries and it's quite challenging to defeat the boss after it gets down to about half health. Great work people! 🥳