I think the only thing that occasionally messed me up - except my own incompetence - was the collision detection and the ball's tail, which didn't seem to point in the right direction. I wanted to praise you for the music excessively but as I just read in the comments you took it from Wild Arms. I guess I can still compliment you for picking fitting music then.
As for the AI, I think it worked, I never felt that it was unfair. At times a little predictable maybe, after a while you could kinda figure out and predict how many exchanges were needed until the AI lost.
Either way, I think it was a nice little game and did what it set out to do. Good job!