The author of that youtube is using features from the MMO golf game known as Pangya in Korea/Japan (or Albatross18 in the US and also imported onto the Wii as Swing Golf).
The Pangya original has some extensive features the others don't have. I believe he's using the Arin avatar as his basis and all he has to do is swap out the model skin files. Damn I'd love to play Pangya/Alb with anime skins like this
-- reminds me of the fun we used to have with the Quake series and the amazing library of avatars people developed for it.
Nonetheless, its damned hypnotic
... this game is the home of the goddess Kooh, a goth-loli type who was quite the popular image last year with her spectacular golf swing moves and celebrating dances.
Update: just noticed, the very last part of the youtube they switch to Kooh for the underlying model engine - that's where those flaming acrobat moves, cannon, and wiggle dances are from.