Super Boss Gaiden makes use of an emulated, prototype "Nintendo PlayStation" BIOS

https://youtu.be/99-v8lkoOdo

The fabled SNES-CD peripheral may have never actually made it to market in the mid-'90s as planned. But that hasn't stopped homebrew developers from utilizing the magic of emulation to make software designed to run on the near-mythical "Nintendo PlayStation."

It's been a long and weird road to get to this surprising point in emulation history. After a seemingly one-of-a-kind "SFX-100" prototype of the SNES-CD was found and disassembled last year, an apparent working version of the system's BIOS found its way to the Internet in March.
Armed with that BIOS file (and some additional sleuthing on components, memory, and IO mapping for the CD-ROM add-on), the latest version of low-level SNES emulator no$sns is actually able to simulate how games would have run on the SNES-CD prototype.

(Warning: we ran into some nasty malware warnings when trying to download and run no$sns ourselves. There's some indication these are compression-related false positives, but as always, let the downloader beware.)

Since there wasn't any actual software released for the SNES-CD's Super Disc format (and no official prototype software has surfaced) it's fallen on homebrew developers to figure out what the system might have been capable of. An extremely simple demo called Magic Floor was released as an emulation proof-of-concept months ago, but Super Boss Gaiden, released this week, appears to be the first full-fledged game designed to run on the newly emulated hardware.

The simple multiplayer brawler goes a bit meta with the Nintendo PlayStation concept, letting you control an unnamed Sony CEO who goes on a rampage when he learns his hardware prototype has leaked to the public and been emulated. Be on the lookout for totally unauthorized appearances from characters like Parappa the Rapper, LittleBigPlanet's Sackboy, and even the Famicom Disk System's Disk-kun mascot as you bust up the offices.

So far, there doesn't seem to be much concrete value in emulating the SNES-CD over the plain old SNES. The Super Boss Gaiden release includes both a standard SNES ROM and a larger Super Disc binary, and both versions seem to look and play practically identically (based on a trailer posted by the developer).

Still, the mere fact that you can now play a game designed for a classic console that never technically existed is a testament to the "do it because you can" spirit of the homebrew community. This is probably as close as you're ever going to get to being able to play a real SNES-CD game, so enjoy the simulated trip into an alternate version of console history.