RecompOne: new open-source tool recompiles PS1 games into native C#

The developer known as Flaffy published a new tool called RecompOne on GitHub on July 21, 2026, a static recompiler that translates PlayStation 1 executables directly into C# code, following the same approach as recent recompilation projects on Nintendo 64. Rather than emulating the console's MIPS processor at runtime, the tool converts instructions ahead of time into native operations, while providing a runtime layer that simulates the PS1's BIOS, GPU and CD-ROM drive.

Castlevania: Symphony of the Night served as the main test case to demonstrate the approach's viability, a fitting choice given how much this cult 1997 RPG remains a technical benchmark of the PS1 library.

Flaffy was careful to note that RecompOne is far from a fully automated magic tool: “I don't like using it personally because I like writing my code, but I can see how it can be useful in more monotonous tasks,” the developer explained, stressing that a reliable recompilation requires understanding both how the recompiler itself works and the target game's internals, something AI cannot accomplish on its own.

The project explicitly makes this point in its own description: “this project is not vibe-coded, AI was not involved in writing the code.” RecompOne is available as a free download from its official GitHub repository, which also offers a tutorial wiki to help get started with a first recompilation.

Source: Time Extension