Museum obtains rare demo of id Software's Super Mario Bros. 3 PC

1990 demo was rejected by Nintendo but led to id's own Commander Keen.

Doom dev shares rare Super Mario Bros. 3 PC demo (update) - Polygon

The phantom PC version of 'Super Mario Bros. 3' by the developer of DOOM is stored in the History Museum - GIGAZINE

Public Commander Keen Forum - Search

Super Mario Bros. 3 PC demo found by New York museum

Museum obtains rare demo of id Software's Super Mario Bros. 3 PC port

id Software

Museum Acquires Rare Super Mario 3 Port Made By Creators Of DOOM

id software News, Rumors and Information - Bleeding Cool News Page 1

Id Software's demo for Mario 3 on PC is now in a museum

List of unreleased media - Super Mario Wiki, the Mario encyclopedia

News - October, 2023

The phantom PC version of 'Super Mario Bros. 3' by the developer of DOOM is stored in the History Museum - GIGAZINE

Super Mario Bros. 3 - Wikipedia

id Software - Wikipedia

Museum obtains rare demo of id Software's Super Mario Bros. 3 PC port