In the title screen, press and hold X+Y+Z+START. Now you can choose the "SP battle" mode in the menu screen and you have will all the characters clear.
When you are playing, press START, then hold X button. (Try, with controller one and controller two, press START button quickly and many times during the game; you'll see a lot of letters in the screen.)
To view a collage that chronicles the evolution of DBZ, beat the game with a high score.
Start off with Super-Saiyajin 3 Goku, then hit Majin Buu with 2 meteo attacks. After the second meteo attack take out Super-Saiyajin Goku and put in Goten and Trunks, they will fuse into Gotenks. Have Gotenks finish off Majin Buu. Then when the 2nd Buu comes in have Gotenks hit him with with 2 meteo attacks then take out Gotenks and put in Gohan. Have Gohan finish him off!! If done correctly the score on the next screen should say 100.
To play as SSJ (Super Saiya-jin) Vegeta 2, you must complete the following tasks:
1. Beat all versions of the game (campaign mode, SP mode).
2. In campaign mode, get the best ending.
3. Play VS mode.
4. Keep choosing SSJ Vegeta and you will eventually get him with no armor.
That is SSJ2 Vegeta. He is a bit stronger than the original SSJ Vegeta. Note: This trick only works in VS mode.
Do this when you are about to fight Freeza. At the character select screen, pick Krillin as your fighter. Then start the game and let Krillin die. Gokou will automatically will become a super saiyajin.