It is a tutorial stage.
The first stage of Sun Sun Island. It takes place on a beach, as the name implies. It has no enemies.
The second stage of Sun Sun Island. It also takes place on a beach. It introduces the Flitter and Neek enemies. A giant flower appears in the stage. Using it will launch the player. Bushes appear in midair as well. Landing in them will make Donkey Kong stick to it. Water is introduced in the stage as well.
Cool Cool Cave
The third stage of Sun Sun Island. It takes place in a cave. Flitters, Neeks, and Flip-Flap appear in the stage. A boulder can be grabbed on and will roll if one grabs it.
The final stage of Sun Sun Island. The player must climb to the peak of the mountain. Flitters and Neckys appear in the stage. The boss, Banana Spaceship, is fought at the end of the stage. It attacks by dropping carrot bombs. After beating it, the player can rescue Diddy Kong, who is inside a DK Barrel.