To get a good score you need a good ear for music, a good memory and a sensitive wrist.
First, you hear a tone to remember. Then you adjust the pitch of another tone, by tilting the phone, until the pitch matches the pitch of the first tone. The closer you get in pitch and the faster you do it, the higher is the score.
Play solo and climb on the highscore list or challenge other players to climb on the ranking list.
This trial version is fully functional but after 5 days you will lose the possibility to challenge others. However, you can still play solo games and climb on the highscore list.