It is a game that slides the white tortoise and drives out all the Roadrunners in the circle.
Shell is Koura in Japanese.
Shoot the White tortoise from the bottom to the top of the screen and hit it against other Roadrunners or Green Tortoises.
When Roadrunners and Green Tortoises hit each other, they bounce off.
Drive all road runners out of the circle with a single shoot and put all Green Tortoises in the circle.
If succeed in making only Green Tortoises in the circle, proceed to the next stage.
The level goes up depending on the speed of clearing.
As the level goes up, the number of Roadrunners and Green Tortoises increases and the stage becomes complicated.
Clear all 10 stages, the total score will be registered on the leaderboard of the game center.