Very interesting mechanic, you should create a tutorial or at least write somewhere how to play, because I must figure out this by myself.
Idea is good, but I feel like some changes are needed, because while its fun, its very unfriendly. I dont knows exactly when the projectiles will start its orbit and when not. Usually orbiting objects stays very close to our character, so trying to push them into boss, make a big and unfriendly risk of collide with a boss. Maybe the boss should not deal the damage just because we touch him, instead he should make a quick melee attack. Or the orbiting range should be much bigger.