Back in the 90s, John Carmack -- a programmer knee-deep in some of the biggest computer video game titles, including Wolfenstein, Doom and Quake -- decided to prove that the PC could do video games (specifically, games using EGA) with smooth horizontal and vertical scrolling; an aspect they seriously lacked, compared to the console market. So he took his character Dangerous Dave and along with programmer Tom Hall and stayed up all night to make this:
Compare to the original:
The goal was to prove to Nintendo that the PC could do everything the Famicom/NES could and, therefore, the newly formed id Software should be allowed to port Super Mario Bros. 3 to the PC. Unfortunately, while they were impressed, Nintendo never had plans to release their properties on anything except their systems, so id never got the deal. However, the research and coding did give birth to Commander Keen -- a game fondly remembered by everyone who grew up on shareware discs. You can read more about it here.