PC versionNES Fans have made a PC version. Some are still early, so read the project page first.
Fans took Super Mario Bros. / Super Mario Bros.: The Lost Levels apart and rebuilt it so it runs natively on a computer, often with widescreen, higher frame rates and mods. Here is the project we know about:
A C decompilation and port of the NES games "Super Mario Bros" and "Super Mario Bros: The Lost Levels"