Game & Watch on ZX Spectrum emulates the Sharp SM510 in Z80 assembly to run 18 Nintendo handhelds on a 48K

Supratim Sanyal's version 1.0.0 runs the handhelds' original 4 KB programs, which you supply from your own copies, and adds Munchy, a new maze game made for the collection.

AI-drafted from 2 sources. This story was written with AI from the outside reporting listed under Sources, and checked by automated tools before it went up. The originals have the full detail.

Here is a sentence I did not expect to write: Mario's Cement Factory now loads from tape on a ZX Spectrum 48K, running its own original program. Supratim Sanyal released version 1.0.0 of Game & Watch on the ZX Spectrum on 6 November 2026, and the trick behind it is an emulator for Sharp's SM510 microcontroller, the chip inside most of the later Game & Watch models, written in Z80 assembly so the Spectrum can run it.

It is not a set of remakes. The project page says the Z80 emulates the SM510 in full at the original chip's own speed, down to every instruction, the clock divider, the keys, the LCD and the buzzer. The handheld's own 4 KB program does the rest, so the logic, timing, sound, Game A and Game B modes and the misses all come from the original code. The README gives the SM510's specs as 4 KB of program ROM, 128 four-bit cells of RAM and a clock of 16,384 cycles a second, which helps explain how a 1982 home computer can keep up.

The games

Eighteen models are supported, across the Wide Screen, Multi Screen and Super Color ranges: Turtle Bridge, Fire Attack, Snoopy Tennis, Oil Panic, Donkey Kong, Mickey & Donald, Green House, Donkey Kong II, Mario Bros., Rain Shower, Life Boat, Squish, Donkey Kong Jr., Mario's Cement Factory, Manhole, Tropical Fish, Spitball Sparky and Crab Grab. Each LCD figure is drawn from graphics made for the Spectrum's screen.

There is a nineteenth game that never existed until now. Munchy (MU-01) is an original Pac-Man-style maze game written for the SM510 with its own drawings and sounds, and like the real thing it keeps time and has an alarm. It plays with Q, A, O and P (or 9, 8, 6 and 7), 1 for Game A, 2 for the faster Game B and ENTER for the ACL reset.

Bring your own ROMs

Nintendo's code is not included. Each game's tape holds a loader plus the emulator and the screen graphics, and the game's 4 KB ROM goes on a second tape that you make yourself. A Python 3 script in the repository, make_block2.py, builds it from a MAME Game & Watch set from your own collection, using only the ROM image. You load the game's tape with LOAD "", then play the ROM tape for the same game when asked. A red border and a stop mean the ROM is missing, belongs to another game or is a revision the tape was not built for. Munchy and a small demo tape need no ROM at all.

The tapes are TZX images, so they work on a real Spectrum 48K or a TZX-capable emulator, and the source for the emulator, tapes, artwork and tools is all in the release. The project states it is not affiliated with or endorsed by Nintendo.

Sources

Image: Image: Supratim Sanyal

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