In story 10 when you fight Frieza with Super Saiyen Goku use beam attacks like Kemehemehe, Spirit bomb and other powerful beams. And if you have Taioken you should add that to your limited selections.
After you clock the game you beat frieza with teen trunks.
Unlock Cell 2nd Form & Perfect:
With imperfect cell beat android 17 to get 2nd form and beat android 16 and 18 with cell 2nd form alone to get perfect cell. Qck-stop-dvce would be really handy here.
Unlock Imperfect Cell:
Easy just beat him with piccolo.
Unlock Ultra Kameha And Super BuuBall Slam:
Finish the game without losing 1 battle and hold start when goku and his family appear. A chime would sound to confirm the code.
Unlock Majin Vegeta:
You MUST have vegeta and his super saiyan form. You lose to majin vegeta as goku ss2 and then you beat him using goku ss2.
The Genie has more Dragon Ball Z: Legendary Super Warriors Cheats