In the Japanese version, and prototype US builds, of DuckTales, the ending line of the game was the grammatically incorrect, and arguably out-of-character, Scrooge line "There really is more important treasure than this, that is... dream and friends", which was changed to "I couldn't have done it without you. I really am the richest duck in the world." for the US release. Darlene Lacey, a producer on the Disney side of DuckTales would say of the partially unused line in a Kotaku interview:

It is possible to finish the game with $0. Upon doing so, you get a special ending where the newspaper reads:

"Scrooge McDuck has lost his fortune in his search for the legendary five treasures. He will use them to rebuild his empire."

In a prototype version of the game, the health restoring item was a cheeseburger instead of ice cream.

The Transylvania theme was completely different in the game's prototype, and the moon theme was originally 20% slower than in the final version.

There's a sprite of Scrooge wagging his tail while ducking, but the reason for removing it is unknown. However, his tail might wag while bouncing on his cane.

The game contains three unused graphics:
• An image of an NES controller. It can be found amongst the ending cutscene data.
• A bomb with no associated sprite data. A similar object appears in Chip 'n Dale Rescue Rangers.
• A sprite of Scrooge wagging his tail while ducking.

The reason Scrooge McDuck wears his red cloak from the Carl Barks comics (which would later be used in the 2017 DuckTales reboot) instead of the blue cloak from the original DuckTales TV series is because the blue cloak didn't stand out enough alongside blue and black level backgrounds.