A game system comprises image obtaining means, direction calculation means, first rotation means, and display control means. The image obtaining means obtains an image taken by an imaging device. The direction calculation means calculates a direction originally determined from the image of an imaging target included in the image taken by the imaging device. The first rotation means rotates an operation target in accordance with the calculated direction. The display control means generates an image in accordance with the rotation of the operation target performed by the first rotation means and displays the generated image on a screen of a display device.