Watch id Software's long lost Super Mario Bros. 3 PC prototype

Before it created Doom, id Software made a name for itself with its Commander Keen series of PC platformers. But before that, it was hoping to port Nintendo games to computers and even went so far as to make a prototype of Super Mario Bros. 3 for PC.

Now, to commemorate Commander Keen's 25th anniversary, programmer John Romero has released the first public video showing what its Super Mario Bros. 3 prototype looked like.

Completed on 28th September, 1990, id (then known as Ideas from the Deep) was testing the waters of its new side-scrolling engine. "Back in the day, side-scrolling on PC was very difficult," said Digital Foundry's tech guru Rich Leadbetter. "id cracked it."

As you can see, it's not as polished as the console game, but it was only created to show Nintendo what it could do. There's few sound effects and Mario lacks the same momentum he does on NES, leading to an awkward infinite jumping approximation of flying. There's also all-new stages, created by id a quarter century before Super Mario Maker hit store shelves. Even if these new levels don't seem as sterling as Nintendo's classic, it's still a fascinating piece of history for the studio that would soon after become famous for games about blasting demons into giblets.

"id Software has always revered Nintendo," Romero said on Twitter. "Their game designs were extremely influential and they saved the industry in 1985."