Donkey Kong Jr. sets out to free his imprisoned father in this port of Nintendo's 1982 arcade game. The action takes place on one of four fixed screens, each featuring platforms and hanging vines or chains on which to climb, slide, or leap across. The goal is to find the key or keys needed to spring Donkey Kong from his cage. Adding to the challenge is an angry Mario, who will release enemies like "snapjaws" that will chomp their way up and down the vines and attempt to bite Junior. Complete all four levels to continue the game at a harder difficulty setting. The NES version features two play options: the normal game and one that begins on the third level.