We never saw an official localization of Mach Rider, but that doesn’t mean that some industrious fans can’t work their asses off to bring the game out via fan-translation. That’s exactly what is going on, which is how this little bit of art was stumbled upon.
Hidden away in the game’s data is evidence of an appearance of Mach Rider, the NES title. I guess this was cut from the final game, and now we’ll never know what the plans were! Thanks to Josh for the heads up.