Puyo Puyo! 15th Anniversary Cheats :
Code - Unlock Everything
From the Main Menu enter the options menu (4th option) From there hold the plus and minus button, it should then automatically enter the config menu. While still holding the plus and minus button highlight the Chain Animation option (4th option) then press up, down, left, right. If done it correctly you'll hear a chime and you'll have all modes, characters and the entire gallery unlocked.