Mario is Missing! was shaped by a Carmen Sandiego rivalry and miscommunication

gamedeveloper.com:

Generally when it comes to Mario games, Mario is the star of his own world. But that shifted in 1993 with Mario is Missing!, a title that broke the series' traditional formula by focusing on exploration over platforming, starring Luigi as he attempted to find his kidnapped brother."

Mario is Missing! was part of a line of educational (or "edutainment") games, several of which were made by Software Toolworks. In a recent retrospective from Time Extension, the studio's lead designer Donald W. Laabs revealed how a rivalry with another famous series played a surprising role in the game's development. 

While Nintendo left the studio to its own devices, Laabs speculated the publisher may not have known what it was getting into during development. He understood that Nintendo clearly wanted an edutainment game, but felt that it hadn't "fully realized what the [Nintendo of America] deal committed the company to."

Even so, the staff was said to be "honored" to make Mario is Missing!. Several staffers like MS-DOS programmer Jeff Chasen, were fans of the series, and said they looked back to the original games often for inspiration. 

Since Toolworks was the first non-Nintendo studio to ever make a Mario game, giving Missing! a distinct identity from the main series was important. According to Laabs, the studio's lead artist had to go to 'Mario art school' to learn how to properly convey the series' characters.

One other way to make the game's spinoff status clear? Molding it after the dominant edutainment franchise at the time. 

Speaking plainly to Time Extension, Laabs admits Missing! was meant to compete with Broderbund's long-running Carmen Sandiego series. "It was thought that a licensed character like Mario would carry a lot of