Game apparatus and storage medium

A display device 12 covered by a touch panel 13 displays a game space on a display screen. Position coordinates (tx, ty) obtained when the touch panel 13 is touch-operated are detected at a predetermined periodic cycle. At least one of a movement speed (V) and a movement direction (theta) is calculated as a movement parameter for a second object based on current position coordinates (tx, ty) and position coordinates (tpx, tpy) having been detected in an immediately preceding time. A new movement parameter (V and theta) is determined using movement parameters having been previously determined (Vp and thetap) and the newly calculated movement parameter (V and theta). When the first object and the second object satisfy a predetermined positional relationship therebetween, the second object is moved and display-controlled based on the updated movement parameter.