I'm not sure if I missed some mechanic, or if the difficulty is just tuned too high, but I could not beat the boss. I could get him stunned, sometimes, but he'd fly too far away to chain any other hits into before he got back up, and I was doing barely any damage.
It sounds like you're planning to keep working on it, and if so, I'll be interested in where it goes. Seems like it has some potential.