MS-DOS
15 projects: 4 decompilations, 0 static recompilations, and the rest ports, rewrites and clean-room builds.
Digger Remastered
Digger
Long-running reconstruction of Windmill Software's Digger in portable C, with enhancements.
DOOM source release
DOOM
id Software's release of the Linux DOOM engine source in 1997, relicensed under the GPL in 1999. Nearly every Doom source port descends from it.
Dwasm
Doom
PrBoom+/PrBoomX-based Doom engine compiled to WebAssembly; you pick an IWAD such as the shareware DOOM1.WAD.
Fasttracker 2 clone
Fasttracker II
Highly accurate C re-creation of Fasttracker II's editor, replayer and quirks.
Freedoom
Doom (game data)
A complete set of freely licensed levels, graphics and sounds that lets Doom engines run without id Software's data files.
MilkyTracker
Fasttracker II
Cross-platform music tracker that reproduces the look and module compatibility of Fasttracker II.
OpenSupaplex
Supaplex
C reimplementation of Supaplex written from a full disassembly of the DOS game, ported to many systems.
OpenTTD
Transport Tycoon Deluxe
Open-source transport simulation that began as a reverse-engineered TTD clone and now runs with free replacement graphics, sound and music.
OpenTyrian
Tyrian 2.1
Portable C port of the vertical shooter Tyrian 2.1, which plays with the freeware game data.
QB64 Phoenix Edition
Microsoft QuickBASIC / QBasic
Compiler and IDE that keeps QuickBASIC/QBasic source compatibility while producing native 64-bit programs.
Quake source release
Quake
The Quake engine source, released by id Software under the GPL in 1999; the base for QuakeSpasm, ioquake-style ports and many engines.
Qwasm
Quake
Browser port of the Quake engine with WebGL and software rendering, mods and mission packs; you supply PAK files.
reSL
ShortLine
Reverse-engineered reconstruction of ShortLine v1.1, a 1992 DOS railway puzzle by DOKA, also playable in the browser.
Schism Tracker
Impulse Tracker
Re-creation of the Impulse Tracker music editor's interface and playback for modern systems.
skyroads-32x
SkyRoads
SkyRoads engine reconstructed from the retail binary and ported to the Sega 32X and desktop.