This was a really fun game that kept me playing for a long time! I wish there was some sort of other island or something beyond the big bosses, but other than that this is a really fun game, I love the progression and it's really satisfying.
One thing is that I wish I could make text go faster, I can read it pretty fast, but I still want to know what it says.
I like the music, it fits the vibe of the game!
One last thing: you might want to change the various rigidbodies' collision type to continuous. It will make the player not jitter when it's colliding with a wall. If you haven't already, you should probably also put your movement code in the FixedUpdate() function instead of Update(), it might also fix some of these problems.