A playable version of id Software's Super Mario Bros. 3 PC port has been unearthed

An unusual piece of game design history – a demo of Super Mario Bros. 3 running on PC, developed by id Software—has been unearthed by the Strong Museum of Play.

Knowledge of the demo’s existence has apparently been floating in the ether since at least 2003, and id Software co-founder John Romero showed it off in a 2015 video.

But yesterday Strong Museum archivist Andrew Borman tweeted an image of the demo, and then confirmed to Ars Technica that he did in fact, have a working, playable version of the unfinished, unreleased game.

The Super Mario Bros. 3 demo was apparently an after-hours project from Romero, Carmack, and their collaborators that was completed on September 28^th, 1990 (under the company’s then-name Ideas from the Deep, or IFD). It was then sent to Nintendo in a bid to land a contract porting the game for PC.

Romero wrote that Nintendo was impressed, but uninterested, and id Software moved to work on the Commander Keen series.

Borman told Ars Technica that the disc carrying id’s Super Mario Bros. 3 port had been sitting in a larger collection of donated software. It came from an anonymous game developer who had “received [it] during their work.”

For a brief moment, Borman was the first person to play the demo in a number of years. He apparently was able to verify its authenticity by comparing it to Romero’s video, and even uncovered a previously unseen version of level 1-4.

The demo won’t be playable by the public anytime soon, but Borman said that researchers and other parties with relevant interests will be able to access it in the museum’s archive.

Though apparently “there are plenty of opportunities to come in the future” for it to be displayed to the public, he stated.

Images via Andrew Borman