Here's something you don't see every day: the Nintendo classic Super Mario Bros. running on the Sega Master System.
For pretty obvious reasons (which we probably don't need to go into), Mario's original sidescrolling adventure was never officially ported to the Sega console back in the day.
However, as part of the SMSPower 2026 coding competition, the Master System developer, LackofTrack, has produced an impressive "proof of concept" showcase of what it could potentially look like running on the Master System, if it did, through some miracle, ever end up making the jump over to the Sega System.
LackofTrack's version so far only includes the first level, so we'd hesitate to call this a "port" just yet, but interestingly, it appears the developer has expressed interest in developing things further, saying they'd like to "add FM sound support at some point," and they are also looking for some help with the graphics.
It heavily uses the NES game's disassembly from doppelganger as a reference, which LackofTrack suggests should mean it "is very (but definitely not 100%) accurate to the original," and also features graphics that appear to be modified from the 16-bit remake of Super Mario Bros. on the Super Mario All Stars Collection.
If you'd like to give it a try, you can download it here. It is currently at version 0.12, with the latest version fixing some power-ups spawning too high and tweaking the underground music to better "reach the lower notes of the song."