To unlock these outfits, enter the code at the "Press Start" screen.
Beat training mode with each of the following charectors to unlock their C costumes. To beat training mode destroy all 8 pillars, and use all their moves. You should hear a ding noise after both are complete.
DBF = Davy back fight
Unlock all the characters to reveal a new title screen that features everyone.
To enter a code, you must first clear Story Mode with any character at any diffculty setting. After you defeat you last opponent and the credits will appear, enter the following codes while the credits are scrolling up the screen: (You can only enter one code after each time you clear story mode)
Clear Event Battle with Luffy, Zoro, Nami, Usopp, Sanji, Chopper, Robin, Buggy, Kuro, Krieg, Arlong, Smoker, Bon Clay, Crocodile, and Foxy. Then play Event Battle again with Luffy and beat Aokiji with a level 2 special to unlock Aokiji.
Unlock characters 1-15 first, including Mr. 2 Bon Clay and the 4 hidden characters: Ms. Sunday, Tony Tony Chopper, Red Haired Shanks and Hawk-Eye Mihawk. Next play as Ms. Sunday in Story mode on any difficutly. Enter the following command as the end credits run.
After clearing event battle with Luffy, Zoro, Nami, Usopp, Sanji, Chopper, and Robin complete some of there move lists in training mode. A picture should flash by of Enel challanging you, go to Grand Tours (tournament mode) and just play a regular tournament, one of the characters will be replaced with Enel, beat Enel and win the tournament to unlock Enel.
Win 3 events in Davy Back Fight mode 3 times.