Theatrhythm: Final Fantasy is an upcoming 3DS Rhythm game produced by Square Enix and Indies Zero, the folks behind Retro Game Challenge. The game almost covers all the numbered Final Fantasy games with Heroes from I – XIII appearing. Players pick a party of four and go through three stages – field, battle, and events, all of which are music games. Characters will also level up, JRPG style, though Square Enix plan to expand on this point later.
The game will draw upon the vast library of Final Fantasy music with the Final Fantasy theme, “Battle on the Big Bridge” (Gilgamesh’s theme) from Final Fantasy V, “One Winged Angel” from Final Fantasy VII, “To Zanarkand” from Final Fantasy X, and “Sunleth Waterscape” from Final Fantasy XIII. having been confirmed by Square as appearing in the game.
Thanks to Siliconera for the info.