Sonic CD (Little Planet)

Game: Sonic CD → (Mega-CD / Sega CD, 1993)

Little Planet: a native port of the Mega-CD (Sega CD) version for Windows, macOS, and Linux (x86-64 and ARM64). It carries a disassembly of all the game’s code that reassembles byte-identical to the disc, and a static recompiler that turns it into C, which is what runs; it’s checked frame by frame against an interpreter. The rest of the machine is written from scratch: both 68000s, the Z80, the VDP, FM, PSG, and PCM sound, the CD drive, and the Mega-CD graphics chip, and no BIOS is needed, since the game’s calls are replaced by a high-level implementation. It adds a True16:9 widescreen mode that shows more of the level instead of stretching the picture (on by default), filters such as CRT or Scale4x, remappable controls, save states, fast-forward, and an automatic save after every zone. It replaces the opening movie with LuanUP’s 4K 60 fps remaster, included with their permission; the original is still available in the settings. It accepts cue/bin, iso, ccd/img, chd, and cue images with wav, flac, ogg, or mp3 audio tracks. Version 1.0 came out on October 11 and is rebuilt with every code change; the latest build is from October 19. Of its 36 commits, 27 list Claude as co-author. The repository includes the disassembly of the disc’s 112 executable files, code only: graphics, sound, and levels are read from your copy.

You needYour own Sonic CD disc image for Mega-CD. The tested release is the Japanese one (G-6021, with the data-track SHA-1 given in the README); other releases boot but are untested. Plus 64-bit Windows, macOS 11 or later (Apple silicon or Intel), or x86-64 or ARM64 Linux.

How it gets to PC

Static recompilation

Console

Sega Mega-CD / Sega CD

Architecture

68000 x2

Author

carl0srmz (formerly carlosrmz009)

Original studio

Sonic Team

Year

1993

Stars

51

Last activity

2026-10-19 · 12 days ago

Latest version

1.0 · 2026-10-11

Language

Assembly

Sonic CD (2011, decompilation) See all →