Donkey Kong Junior is the arcade game Nintendo released in 1982 as a direct sequel to Donkey Kong, with a narrative twist that reverses the roles: now Mario is the villain keeping the gorilla locked up, and his son must climb vines and platforms to free him. It was one of the early examples of a saga expanding its story from one installment to the next.
It's a solid platformer within Nintendo's early crop, with a climbing mechanic that gives it its own identity against the original. It never reached the cultural significance of Donkey Kong or Mario Bros., but it remains a key piece of the company's early catalog.

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