More details about the music/rhythm game Idolmaster Shiny Festa come from Famitsu which announced the "Star of Festa" mode. This five day event is locked until you get enough fans and improve your idol rank.
Each day in Star of Festa mode has three songs to play. The third stage is an idol battle where you’ll have to perform live against 876 Productions, 961 Productions, and Cinderella Girls (from a social Idolmaster game). Beat the rival idols and you get a business card as a reward. Star of Festa mode takes place over five days where votes are cast on who is the best idol group.
Idolmaster Shiny Festa is actually three separate titles – Idolmaster Shiny Festa: Funky Note, Idolmaster Shiny Festa: Honey Sound, and Idolmaster Shiny Festa: Groovy Tune. All three games come out on October 25.