A CPU core of a game machine displays a game image on an LCD, executes a game process, and performs an updating process on the game image. Also, it is determined whether or not a result of the game process satisfies a predetermined condition, and if the result of the determination is affirmative, a touch coordinate is detected via a touch panel, and the result of the detection is transmitted to an opponent's game machine through a wireless communication portion. A touch coordinate from the opponent's game machine is received by the wireless communication portion at an arbitrary timing. Thus, when the opponent's touch coordinate is received, the CPU core displays an obstacle at the touch coordinate position within the LCD.