One Piece: Grand Battle

After unlocking Shanks and Mihawk, successfully complete the entire move set for all The Straw Hat Pirates in Training mode to unlock a third costume for them inspired by the Color Walk books. After unlocking the third Straw Hat costumes, successfully complete Grand Battle thirty times or Event Battle six times, with each of the Straw Hat crew to unlock a fourth alternate costume.

Unlock all the characters to get a new title screen that features everyone.

Successfully complete Event Mode with Mihawk on the hard difficulty setting to unlock the "BMG Select" at the "Treasures" menu.

At the "Press Start" screen, hold R, then press Left, A, Right, X, Y, Left, Right, B to unlock Chopper's fourth costume.

Win the Davy Back Fight min-game the indicated amount of times to unlock the corresponding bonus:

Groggy Ring: 4 times
Donut Race: 10 times
Crash Rush Boxer (the box breaking): 18 times
Snow (getting rid of snow): 26 times
Breaking Krieg's Armor: 29 times
Sanji & Zoro voice (announcing): 33 times; also need all support character voices unlocked
The "Fix" sign: 34 times

To get extra attack add-ons for Luffy's Gum Gum Scythe attack, you must have over four fruits when using this attack. Once you attack, after your opponent hits the wall press X and you will hit your opponent in the air. Then, keep pressing X. You will do another add-on. You will hit them in the air. Then, keep pressing X. For the final attack add-on, you will hit them up again. Luffy will count down to "1" then he will yell and twist like a spiral, bounce up, and smash your opponent through the roof of the building. If you KO your opponent while doing this trick you will see the building fall around Luffy and he will say, " I'm gonna be King of the Pirates!" and you will win. Note: This trick works well with over four fruits and if your opponent health is down slightly past halfway.

Win all three rounds of Usopp's Pirates' Challenge to unlock the announcer as a System Voice.

After unlocking everyone, successfully complete their move lists in Training mode. After doing so, destroy all the pillars in the stage. Do this with every character to unlock the stage.

Instead of holding L and pressing A + B to use a random clone-clone attack, try the following moves to transform instead. By doing this, you can use strategy instead of luck for which character you will transform into.

Mr. 7: While holding L, press A(4), B.
Mr. 8: While holding L, press A(3), B.
Mr. 9: While holding L, press A(2), B.

Successfully complete 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. In the final stage you will battle Aokiji. To unlock Aokiji, you must use your level 2 special.