Crazy Kong was an officially licensed clone of Donkey Kong released by Falcon Inc. to compensate for Nintendo's inability to make enough Donkey Kong machines as there was demand for. However, Crazy Kong was only allowed to be distributed in Japan, but Falcon released the game abroad anyway with Elcron Industries, leading to a lawsuit where Nintendo won.

In the arcade versions of the game, there's a hidden message in the files:

While the first three lines were overwritten with other data in the American build, the rest survived unchanged.

According to court documents related to the 1983 legal case Universal City Studios, Inc v. Nintendo Co., Ltd., 19 alternate names considered for Donkey Kong included:

• Funny Kong
• Kong the Kong
• Jack Kong
• Funky Kong
• Bill Kong
• Steel Kong
• Giant Kong
• Big Kong
• Kong Down
• Kong Dong
• Mr. Kong
• Custom Kong
• Kong Chase
• Kong Boy
• Kong Man
• Kong Fighter
• Wild Kong
• Rookie Kong
• Kong Holiday

The name "Funky Kong" would coincidentally re-emerge as a character in Donkey Kong Country.

According to series creator Shigeru Miyamoto, Mario's appearance was the result of graphical limitations in the original Donkey Kong: his overalls allowed his arms to be visible against his body (as there was no room for outlines), his hat substituted for hair and eyebrows (and did not need to be animated when he jumped), and the large nose and mustache made up for the lack of space to depict a mouth.

Miyamoto additionally stated that the design was influenced by the decision to make Mario Italian-American, identifying his large nose in particular as a distinctly western feature.