Thanks for checking out the update! Glad the controls worked better for you, I hadn't gotten any feedback about that.
As for the Stage 2 boss, I'm of split mind... your comments kind of make me want to update it. On the other hand, the B-Side was intended to be difficult. The stages themselves are still pretty easy, so I wanted the bosses to be a real challenge. I'm pretty sure I got a comment somewhere (maybe on the jam discord) from someone who cleared the B-Side. I still find it a mild challenge, but can blow through it with a retry or two in most cases.
The second phase of the "lock" boss looks flashy, but is actually easier IMO.
Anyway, thanks so much for checking it out! I'll have to think about this for awhile.