Picture a lilac-coloured Japanese console from 1995, designed to print sticker photos of anime characters, marketed almost entirely at young girls. Now picture it running DOOM. That contrast is exactly what developer Throaty Mumbo has pulled off, completing a port of id Software's legendary shooter for the Casio Loopy, one of the most obscure retro systems ever made.
The Casio Loopy launched in Japan in 1995 as a 32-bit console with a built-in thermal sticker printer baked right into the unit. Its library leaned heavily into cosy and romance titles, its shell came in pastel lilac, and it sold in modest numbers before quietly disappearing from shelves. It never left Japan. It never got a serious action game. And it absolutely never got DOOM. Until now.
The flash cart that made it possible
The key here is the Floopy Drive, an open-source flash cartridge built specifically for the Casio Loopy. Throaty Mumbo had already been experimenting with the device, running homebrews like "Floopy Bird" and a DOOM-inspired title called "Anarch" on the hardware. Those experiments apparently lit the fuse. The developer decided to go further and attempt a genuine DOOM port, taking the SNES version as the primary reference point for scope and approach.
The process started with getting the game running in an emulator before attempting to push it through the Floopy Drive onto real hardware. The first real-hardware attempt ran slow and had no MIDI audio. Two more days of work fixed both problems.
Getting DOOM's audio to behave on 1995 sticker hardware
What most players miss when they see "DOOM runs on X" posts is how much work goes into audio. Both DOOM and the Casio Loopy use MIDI, but the shooter was designed around the Roland SC-55 sound font. That mismatch meant drums and instrument layers came out desynced and wrong on the Loopy's hardware.
Throaty Mumbo went through each instrument individually to find more appropriate tones for the Loopy's sound chip. The result is close enough that the DOOM soundtrack remains recognisable, which is no small thing on hardware this far outside id's original target spec.
That still left sound effects. The solution involved physically modding the Floopy Drive to support PCM audio output, using a Raspberry Pi RP2040 microcontroller board paired with a PCM5102 digital-to-analogue converter wired into the cartridge pins. The result: MIDI music and PCM sound effects running simultaneously on a console that was built to print photos of anime characters.
How the visuals hold up against the SNES version
The port looks blocky by modern standards, but that is entirely expected. What matters is the comparison to the SNES port, which Throaty Mumbo used as the benchmark. The Loopy version holds up well against it, which is actually impressive when you factor in that the SNES had access to the Super FX chip on its cartridge to help push the 3D rendering. The Casio Loopy has no equivalent co-processor assist. The fact that the visuals are competitive without that hardware leg-up says a lot about what Throaty Mumbo managed to squeeze out of the platform.
The sticker printer gets the last word
Throaty Mumbo also built a custom label for the DOOM cartridge, leaning into the Loopy's pastel aesthetic rather than fighting it. The finishing touch is exactly what you would hope for: a Cacodemon screenshot printed out as a sticker using the Loopy's built-in printer, then stuck into a scrapbook alongside the console's usual kawaii output.
The "can it run DOOM" tradition has claimed some genuinely strange hardware over the years, from pregnancy tests to ATM machines. The Casio Loopy stands out not just for its obscurity but for how completely wrong it feels as a DOOM platform. A sticker-printing, pastel-coloured, Japan-only girls' console from 1995 running a working port of one of the most iconic shooters ever made, with functioning PCM audio, is the kind of thing that makes retro homebrew worth following.
If this kind of lateral thinking across genres and hardware appeals to you, the puzzle games section has some equally creative takes on what games can do within tight constraints. For something that plays with perception and memory in ways that feel similarly unexpected, Lorelei and the Laser Eyes is worth your time, and the full Lorelei and the Laser Eyes guide collection is there when you need it.
