A simple funny game.
Shake will test your hand speed. This is a very simple game, you can easily get started without any tutorial.
You just need to shake your cell-phone and don't need any other operations. In addition to hand speed, it also test your endurance. Maybe you can put it as a fitness tool to exercise your hands. If you can keep the speed of shaking, I believe you can get a high score.
When you get a high score, you can challenge your friends. Shake support charts. Let's compete with the global players.