Dragon Ball Z: The Legacy Of Goku

Invincibility:
Press Up, Down, Left, Right, B, A when the introduction song plays when the game is first started.
A sound will confirm correct code entry.

In-game reset:
Press A + B + R + L + Start + Select during game play to return to the title screen.
Note: This does not erase your saved game(s).

Completion bonuses:
Successfully complete the game (including all the quests and sidequests).
Start a new game to begin with unlimited energy.

After completing the game, you should have one of two things: unlimited energy or the ability to carry four Senzu Beans.