I was requested to test out the senpuukon (mash punch) special move on DreamCancel's forums, to test whether it negated projectiles (which it doesn't :( ), and whilst trying it i found that Billy does a little animation at the end of the move if you mash the button long enough.
It's a little similar to what they did with Kensou's crazy punch special move (where he keeps punching you until he gets tired) and quite a nice little touch.
Although Billy's standing animation is, for lack of a better word, pretty shit it does however show they have put quite a bit of work into him.
He also spins his stick around a bit after he does his NeoMax.
If they add just a tiny bit more animation into his standing pose he could be one of the better animated characters in the game, as he already has quite alot of animation in his moves.