Stage select:
Hold X + Y + Z + Start at the title screen. Select the "SP Battle" option from the menu to select any character's stage.

Remove paused text:
Press Start + X during game play.

Remove menu text:
Press X, Y, or Z at a file or menu screen.

Gallery mode:
Achieve a high score to view a gallery that features different Dragonball Z scenes.

Fight as Super Saiya-jin Vegeta 2:
Successfully complete all game modes, including campaign mode and SP. Unlock the best ending in campaign mode. Select versus mode, then keep selecting Super Saiya-jin Vegeta until he appears with no armor (Super Saiya-jin Vegeta 2).

Fight as Super Saiya-jin Gokou:
Select Krillin as a character at the match against Freeza. Begin the match and intentionally allow Krillin to be defeated. Gokou will automatically will become a Super Saiya-jin.

Hint: Level up Saiyajins:
Any of the Saiyajin's (except Nappa) can become stronger. Constant use can make them stronger (especially Adult Gohan, Adult Trunks, and Young Super Saiyajin Gohan). This also carries over to the other modes.