A detection device detects positions at which a sword-shaped controller traverses first and second sensor planes, which are formed by first and second sensors, respectively, and positions of which are associated in a one-to-one manner to positions on a screen. A position on the screen, an amount of change in the position per unit time, an absolute value of the amount of change of the position, and an orientation of the sword-shaped controller with respect to the screen are obtained from input information from the detection device. At least one of a special-effect image, a sound effect, and a parameter that causes a change in the special-effect image is changed, based on one of the obtained position, amount of change in the position per unit time, absolute value of the amount of change in the position, and the orientation of the sword-shaped controller, so that a special effect is changed with respect to the operator of the sword-shaped controller.