Awesome game and super fun!
I figured out a strategy for the last boss that trivialized it somewhat but it was fun to figure out.
If you think of the players as moving around the circle as a clock and stick to around 10 and 2 oclock with the player and saw blade.
You can remove 99% of the projects and hurt the boss. You never have to move more than 10 and 2 oclock,
After I figured this out, I tried it on the other other bosses and it doesn't really work.
I think this is due to the size.
If you were to build on this game my suggestion to having larger bosses would be increase the circle size the player moves "zooming" the player out. As I think when the angle the player can attack from is too shallow, it trivializes the fight. Maybe the player could move to different radius to dodge attacks? like 2-3 different loop tracks?
Awesome game. Really really fun!