Tokyo 7th Sisters

This app is sooo addictive... There are lots of so called "music games" out there, but this one is definitely my favorite one. This game is a combination of a "rhythm game" and "character cards collecting game". The app has also a battle system, where you fight other players using your cards which are coming with stats like HP and attack, and some special skills. Theses cards will also get stronger by leveling them up. Besides Idol Master Cinderella Girls, it has definitely the best character designs. In terms of story and available songs, this one is definitely the top one. Compared to others music games, in this app you only have to tap with 2 fingers, so it is also good for playing on the go. Still doesn't mean that this app is easier to master than the other ones. New cards are released almost every week, with changing events also every week.