What was done
Mr. Matt reached 100% byte-exact decompilation of the Sega Saturn version of Sonic 3D Blast with Claude Opus and Claude Code speeding up the work, and is building a native C and SDL port on top of it.
Mr. Matt (@TheOneMrMatt) is building a byte-exact matching decompilation of Sonic 3D Blast for the Sega Saturn, with Claude Opus and Claude Code speeding it up. Decompilation reached 100% for the US release in September 2026, and a native PC port built on the decompiled code is under way.
How it was done
He began by disassembling the SH2 code and analysing frame by frame dumps of VDP1, VDP2, RAM and SH2 registers from a custom Saturn emulator. Claude Code recreated the Saturn's Hitachi compiler environment from scratch, which took the Special Stage engine (SSSS.BIN) from 3.36% to 56.11% coverage in one day; that binary later became fully byte-exact, as a mix of C and hand-written assembly. The other binaries were built with a specific GCC version he could not find, so he took a similar approach there. He says acceptance tests and other guardrails keep the code clean and matching, and that AI cut years of work to a few months.
Results
The PC port is written in C with SDL, is software rendered with OpenGL for the final frame, and does no emulation. It supports widescreen and plays the attract sequences as on the Saturn. Assets load from the user's own disc files for the US, EU or JP release. Source and binaries are promised for GitHub, with a first release planned for 20 November 2026.
