- Not to be confused with World 9-9.
|Time limit||150 seconds|
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The level starts out with Mario and Pauline on a platform. Donkey Kong then shakes the ground, destroying most platforms on screen and knocking Pauline off-screen and Mario to the ground. By using mushrooms, Donkey Kong grows to a gigantic size and the final boss fight against Donkey Kong begins, with only three platforms remaining in the level. Mario can stand on Donkey Kong's face and fists to reach the platforms. Donkey Kong slams the ground with his fists, causing barrels and barbells to drop from above. To defeat Donkey Kong, Mario must handstand and kick barrels with his feet, causing them to land on the platforms. Mario must then pick up and throw these barrels at Donkey Kong's head to damage him. However, if Donkey Kong slams the ground, any barrels on platforms break.
After taking two hits, Donkey Kong can attack by slamming his fists together horizontally, causing Mario to lose a life if he gets caught between them. After taking four hits, Donkey Kong quickly slams the ground with one of his fists, causing several barbells to fall from above. After taking six hits, Donkey Kong falls off-screen and is defeated. Once Mario defeats Donkey Kong, Pauline walks onto the screen and Mario and Pauline walk towards each other.
- When selecting this stage on the Tower world map, the top of the tower, which resembles Donkey Kong's head, grins, foreshadowing the battle against Donkey Kong.