In a related but significantly less confusing bit of news, the game is apparently being developed by indieszero, best known for its work on Electroplankton and Retro Game Challenge. Gameplay still hasn't been defined in the strictest sense, but it seems that players will be able to choose characters from Final Fantasy I through XIII in stages based on the baker's dozen of primary FF titles released over the past quarter century.
Each stage is said to be divided into three distinct pieces ("field," "event," and "battle") with three unique gameplay systems, though those systems have yet to be explained. Long time FF fans will be happy to hear that the four-person party system of past titles will return in Theatrhythm, and "major songs" from the series' history will accompany the gameplay. "The Sunleth Waterscape" from FFXIII and "One Winged Angel" from FFVII are specifically named, among several others.
Beyond that, well, there's a chibi Behemoth (seen above). We've dubbed him "Purpular," mostly because he's adorable, but also, ya know, he's purple.