In a game system in which two related virtual game spaces are separately displayed on a first display device and a second display device, an object, contained in a first game space represented by a three-dimensional coordinate system, is displayed on the first display device, and an object, contained in a second game space represented by a two-dimensional coordinate system, is displayed on the second display device. A coordinate conversion process is performed in which coordinates indicating a current location of the object in the first game space are mathematically projected onto a two-dimensional plane within the first game space that corresponds to the second game space, so as to determine coordinates in the second game space, that are indicative of a location where a shadow of the object would occur in the two-dimensional plane of the second game space when produced by a light source positioned at a predetermined location in the first game space.