Donkey Kong Jr + Jr Lesson (Japan)

In Donkey Kong Jr., players control the titular character, Donkey Kong Jr., the son of Donkey Kong. The objective of the game is to rescue Donkey Kong, who has been imprisoned in a cage by Mario. Mario, acting as the antagonist this time, holds the keys to the cage and guards the ape father and son.

The game consists of four unique screens, each repeating with increasing difficulty. To complete each stage, Donkey Kong Jr. must ascend, avoiding obstacles and enemies dropped by Mario. Obstacles include birds, fish, and other creatures. Donkey Kong Jr. can jump, climb vines, and chains to navigate through the levels.

A distinctive aspect of the gameplay is the ability to climb two vines simultaneously for increased speed. When climbing two vines, Jr. slides faster but is also more vulnerable to attacks. Jr. can drop fruit from above to defeat enemies or earn extra points. Each level has a distinct style, requiring players to adapt to different types of obstacles and movement patterns.

The ultimate goal of each stage is to unlock Donkey Kong's cage by collecting scattered key pieces. Once all key pieces are collected, Jr. will open the cage and rescue his father. The game then loops with increased speed and more enemies. The Japanese NES version of the game includes an additional "Jr. Lesson" mode, which provides basic tutorial levels on how to play and essential skills, making it easier for new players to grasp the mechanics of Donkey Kong Jr..