The players have between them a screen with five knobs in it. These knobs link chutes running from the top of the game to its base. The top chutes are loaded with your coloured discs in sequence (1 through 5). On your turn, you twist one of the knobs so as to move one of your discs down. The knobs don't have the same indentations for either player, so you're never sure if you're helping the opponent or not.
First one to get his discs down to the base in sequence wins. You also win if you force the opponent's discs to get to the base out of sequence. Several variants are offered in the rules.