Namco's Splatterhouse series began life in the arcades before transitioning to consoles with its direct sequels (both on Sega Genesis / Mega Drive) and its Japan-only spin-off, Splatterhouse - Wanpaku Graffiti.
That cute Famicom title was intended to get an RPG sequel of its own, named Splatter World, which was intended to launch in March of 1993 but was ultimately cancelled.
It's not known why this happened, but promotional materials were being distributed to Japanese retailers at the close of 1992, so the game was clearly very close to being finished.
Splatter World has been a highly sought-after title for some time, and we experienced a Halloween miracle at the end of last week when the game was dumped and released online.
As reported by the Splatterhouse fan site West Manison, the ROM was uploaded to 4chan. It currently only works on the emulator FCEUX, which is apparently due to its use of an obscure Namco mapper.
However, it's surely only a matter of time before hackers make it compatible with other emulators.