After the success of the fan-made NES/Famicom Rockman 7 port, the denizens of 2ch saw fit to give Rockman 8 the very same treatment and recreate the PlayStation/Sega Saturn original down to the NES format. A year has passed since development began, and although the project isn't quite done yet, the game is far along enough in development to yield a playable demo, which you can download right here.
I haven't played it myself yet, but having compared footage between the "demake" and the original RM8, the game seems like a pretty solid and faithful recreation.
Look forward to the full game's release later this year. Thanks, Henk-Jan.