Donkey Kong Junior is a platforming game and the sequel to the arcade classic Donkey Kong, starring Donkey Kong's lesser-known son Donkey Kong Jr. It is one of the very few official Mario games where Mario plays the role of a villain. After the events of Donkey Kong, Mario has decided to cage up Donkey Kong possibly for revenge over him kidnapping Pauline. Donkey Kong Jr. must now save his father and brave all sorts of traps and hazards Mario has set up for him.

aiqiyou and Fortranm in this new run of the Atari 2600 version of the game save 32 frames over the previous run thanks to better enemy AI manipulation.