Fairly easy/simple music game
Unlike the original Idolmaster, this game is just a music game. You choose the character(s) that you want to perform, and then you choose the song you want to perform. Set the difficulty/other options, and then perform the song. It's that simple.
The achievements for this game take no time at all. And there really isn't much to it. The game can be easily played without any knowledge of the Japanese language.
All that said, I did enjoy my time with the game.