hello fellow GM studio user!
everything felt nice, the graphics, music, art and especially the boss fight was very satisfying and well made to a crazy high level
my only issue is when you drop into the lava, it is almost impossible to get back up. I was only able to back to the floor once out of maybe a dozen attempts where I fell into the lava. It was very frustrating when I reach the last phase when there's little room and a fist pushes me outside because I couldn't get back up
I think you could have made at least climbing the wall easier since it's not integral to the boss fight. I did jump on top of the boss hand a lot but that didn't feel like it used the same mechanic as stabbing the wall and dropping
Aside from this I really enjoyed it, it's by no means easy especially since you have to learn the game as you fight the boss, there wasn't much prior training on the game mechanics.
good job!