This is a very misunderstood game. Personally, I love it to death, and I beat the pants off it many times. Its very original.
I had a crisis some time ago, and had to sell it though, so I haven't played it in probably 8 years, and I can't remember everything.
Basically, right is advance, left is retreat, and up and down make you fly, if you are old enough...I think. I think one button is attack, and the other is...block?
The goal is to beat the guy down so the advantage bar is all your color. At that point it will load a screen where you can chose super moves. If you blow all your chi trying to get to this screen, you won't be able to do much with it, so conserve your chi.
Once you are at that screen, different combinations of the kanji cause different super moves. Often times you have to do just the right move to advance the story, such as the surprise kamahamaha on Tao Pai Pai. If you don't do the move, the dude won't die, or something like that.
The game follows the entire DB, and DBZ storylines stopping...right where the manga did, and the anime should have.