GamingAmigaSuper Mario Bros.NESport
Super Mario Bros. now runs on a 512 KB Amiga from one disk, a fan port that says it matches the NES frame for frame
The author, who posts as Agnus Copperfield, translated the game's own code to the Amiga's 68000 processor, which makes this a different animal from the Amiga Mario demos that came before.
On November 12, 2026, a user posting as Agnus Copperfield uploaded a Super Mario Bros. for the Amiga and opened its description with one line: “The NES original, on the Amiga.”
The listing runs eight terse lines, and each one is a claim. “The game’s own code, translated to 68000.” That reads as a translation of the NES game’s instructions for the Amiga’s Motorola 68000 processor, not a rewrite from scratch and not an emulator running a ROM image. “Any Amiga with 512 KB chip.” That is the memory of a base Amiga 500, the machine that leapt past the Commodore 64 five years earlier. “One disk, PAL and NTSC.” The whole thing lives in a 923.6K item, with the zip at 900.5K.
The line that makes it a story is the last test claim: “Checked against the NES on every frame: 163 movies, 5,249,323 frames and steps.”
Do the division and that is roughly 32,000 frames and steps per movie, 163 times over. The listing doesn’t define a “movie,” though among NES emulator users the word usually means a recording of controller input replayed through the game. A replay is unforgiving. If a port gets a jump height or a scroll position wrong by a hair, the recorded button presses stop landing where they did on the real game, and the run falls apart. Mario jumps through hoops for a living, and the author claims this port jumped through 163 of them.
The Amiga has had Mario-shaped projects before. In 2016, Indie Retro News covered Other Super Mario by a developer called Retro1234, a demo with one level, “no game over sequence” and, as the outlet put it, “very floaty” jumping. The coverage said a full game looked unlikely, since the developer might only add the odd level over time.
This new port takes the other route. It starts from the NES game’s own code, so the physics are Nintendo’s and not someone’s best guess at them, and the proof offered is the frame count.
One line in the listing deserves a second look: “PAL and NTSC.” The NES ran at about 60.0988 frames per second in North America and about 50.0070 in PAL regions, according to the Speedrun Demos Archive, which adds that “Due to PAL systems running at a slower framerate, Mario’s movement speed has been increased to counter the effect.” So a single disk that behaves correctly in both regions has to carry two sets of timing, and match whichever NES the movies were recorded on. The listing doesn’t say which region’s recordings make up the 163.
The listing also says “Fact sheet in the zip,” which this story has not read, and closes with a disclaimer: “Fan project. Not commercial, not for sale, not condoned by Nintendo.” The page links no source repository and no author site, and it offers no preview.
The Amiga crowd will probably be the first to find out whether the claim holds. They know this machine’s quirks and they know what a wrong jump feels like. The listing’s own wording, “checked against the NES,” describes a method, and a method can be rerun by anyone who wants to try to break it.
If it holds, the method is portable: translate the original code to the target’s processor, then replay recordings until nothing differs. The 68000 turned up in plenty of machines besides the Amiga, and the technique does not care which one it lands on.
“Not condoned by Nintendo.”