To provide a characteristic game control technique appealing to the visual sense of a user.

An initial image Ii is displayed on a display (S10). The initial image Ii is deformed with time (S14) to assimilate the initial image Ii to the final image If based on mapping data MD describing the correspondence between a final image If and the initial image Ii. A command input from the user is monitored (S16) during the deformation step and, when a prescribed command input from the user is detected (Y in S16), a plurality of alternatives including one alternative Af corresponding to the final image If are displayed on the display (S20). Whether the alternative Au selected by the user is accorded with the alternative Af corresponding to the final image If or not is determined.