The game includes an impressive physics implementation, as the rings have a simulated magnetized state that causes them to stick to other rings and objects.
Use the left and right arrow keys to rotate the wheel, press space to temporarily increase the speed at which the rings fall. The center of the wheel previews the next two (2) rings that will fall. Look for the small arrow along the edge of the rim to know from where the next ring will fall.
The game is over when any of the rings touches the outter rim, which closes-in gradually as time passes within each level. Click.