A puzzle image to be solved, and a duplicating block for creating a duplicate character as a copy of a player character are displayed. The duplicate character is, on the basis of at least a fact that the player character is superposed on the duplicating block, generated in the superposed position. A time limit is set for displaying the duplicate character. Then, when a formation or an arrangement pattern formed by the generated duplicate character and the player character satisfies a predetermined condition indicated by the puzzle image, a change, such as displaying an image of movement of a block or opening of a door, for example, is applied to progress of the game.