Probably the least-known of the Atari System 1 games, Peter Pack Rat featured an original set of cartoon animals, led by a pack rat whose goal is to collect all the random junk strewn about each level. Peter Pack Rat is a hybrid of platformer and maze game with a jazzy, eclectic soundtrack, and while its levels can be a little visually confusing at first, its a game that grows on you. The original cabinet sported a bright blue joystick identical to the original Battlezone joystick, only... blue.
Check out the rest of the Atari System 1 games on the theme pack page.