Pass all story mode on hard mode and you unlock kid buu saga you deafeat buu by throwing a spirit bomb after you pass the whole game I know cheat codes for budokai tenkaichi 2 and 3 so ask me later my name is desi nevarez
Choose "Options" from the main menu, then press Up,Down,Up,Down,A,START,X,START,Y,A,Y,A,X,X,B at the Options menu. This code unlocks all stages in Play Sagas mode, all items at the Extras menu and all stages, and characters in Pendulum mode.
My friend and I were just playing around collecting more Z-Coins and figured out that on the level where you have to fight nappa you can completely exit the level and fly around in nowhere! to do this, just fly around at the place that a baddie stands shooting at you on the top of a building, just before you meet the first orange dinosaur guy that calls the other men. just try to get on top of the house thing that looks like it has horns on it. it works best if you try this at the meting place of the grassy hill and the building. when you manage to do this, you should be able to go through the house and the hill behind it! you can have some fun here then climb the mountain next to the hill (this is not easy) and once you get over it you will fall into an endless abyss! you can turn on friendly fire and have a few duels here if you want. (you must be flying) Or you can keep falling untill your players and everything else on the screen start leaving marks all over the screen.(i dont know how else to describe it) (you'll know what i mean when they do) after they start doing this you can have some fun by shooting your charged blast at the screen making it almost impossible to see. (just dont stop flying unless you want to get caught in an almost unstoppable cycle of your characters falling off the screen and warping back) the only way to get back to the level is to reset the gamecube. good luck because this isn't easy to get started, and have fun trying.