You will have to re-enter the code if you turn the power off to the Nintendo 64 system. On the Title screen, choose Arcade, then choose 1 on 1 battle. On the Character select screen, have Player One choose the Group button at the bottom center of the screen and the computer will automatically pick the first character on the screen for you to play. Have Player One keep winning and keep choosing the Group button until all the characters have been chosen and Player One has won all the battles. You will have to re-enter the code if you turn the power off to the Nintendo 64 system.
Most Characters only have two different outfits, but some have up to three.
On the Title Screen, choose Options. To exit the menu, highlight Exit and press the A Button. If you choose On, the game will automatically end after defeating the first Character in Arcade Mode and you can view the ending. For Fatalities 1, Fatalities 2 and Level Fatalities - although all three codes may be enabled, only the topmost code that is turned on will be active. You must first enter the Secret Options Menu.