Believe it or not, the details below actually from a Japanese PlayStation magazine – specifically, Dengeki PlayStation. The magazine sometimes has reports on high profile games, such Theatrhythm Final Fantasy.
– Three modes of play: Music Game, SpotPass, Museum
– Three submodes for Music Game: Series, Challenge, another mystery mode
– Options are shown with your current party, listed with HP and level
– Swap out characters from your party
– Icons move across the screen
– Three icons: Red, yellow, green
– Red: Touch the screen briefly
– Yellow: Slide in the direction of the arrow or line of movement of the icon
– Green: Touch and hold down on the screen
– Field: Play to field, town and dungeon music. There’s just one rhythm line here. The difficulty is lower, and there are some more relaxed songs that require you to slide the touch pen up and down.
– Battle: There are four rhythm lines here. The music is higher tempo and the difficulty higher. It appears that you’ll be able to get critical attacks by timing your inputs perfectly.