Unlock Staff Credits game: Simply beat the first World to unlock the Staff Credits game under the Options menu.
Unlock Worlds 9 and 10: In order to unlock Worlds 9 and 10, do the following:
Effect - Code: World 10 - Complete World 9 without continuing. World 9 - Complete Worlds 1-8 without continuing.
Play as Grandpa: Successfully complete all stages with all bananas and hidden bananas.
Acquire Sinking Swamp World: Finish each of the default 8 worlds without utilizing any continues to acquire a crown in all of them to get a ninth world called "Sinking Swamp".
