A day-old project rebuilds Chrono Trigger in C, checked frame by frame against the SNES game

BelthasarProject reimplements the 1995 RPG routine by routine against an embedded SNES core, with optional widescreen and 60+ fps. It is not yet verified playable start to finish.

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.

A repository called BelthasarProject appeared on GitHub on 11 October with a native C version of Chrono Trigger, Square's 1995 SNES RPG. It is one day old, so treat it as an early public release. The name comes from Belthasar, the Guru of Reason who designed the Epoch, and the README says it was chosen to keep clear of the "Chrono" trademark. It contains no part of the game: you need your own dump of the USA cartridge, which the setup checks by size and SHA-1 before building anything from it.

The zelda3 method

The README describes the project as neither a byte-matching disassembly nor an emulator, but "a portable C engine that behaves like the game". It follows the approach of zelda3, the native rebuild of A Link to the Past: the original ROM runs in an embedded SNES core built on LakeSnes, called the oracle, and a routine counts as ported only when the oracle and the C code agree. The tooling can step both side by side and report the first frame where they differ.

The field, battles, menus, shops, the overworld and the music now run on the C engine, according to the status table. It reports 253 of 255 enemy fights matching the cartridge, and the field's script interpreter covering 99.9% of script sites. It also lists what is left. The sound chip still runs on LakeSnes's SPC700 emulation, and five timing-sensitive sequences, the motorcycle race among them, are ROM code translated instruction by instruction. The project calls those debt to replace. The README is also plain that the game is "not yet verified playable from start to finish".

Widescreen and more frames

An F1 overlay holds the optional mods: widescreen at 16:9, 16:10 or 21:9, internal resolution from 1x to 4x, and "frames between", which draws extra frames at the display's refresh rate for one frame of added latency. Menus are still pillarboxed. With every option at its default, the README says, the game is the vanilla game.

There is no prebuilt download. Windows with Visual Studio 2022 is the reference platform and Linux builds too, and the first setup from your ROM takes about 15 to 20 minutes. The code is MIT-licensed. The README says much of the reverse engineering, the C and the documentation "was written with Claude Code (Anthropic) under the project owner's direction", and the repository publishes the instructions given to the coding agents.

Sources

Image: BelthasarProject

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