DOS

Memory manager for DOS PCs with 386 or higher CPUs, released by Qualitas company in 1992. Source code was released in June 2022 on GitHub with GPL-3.0 license.

JavaScript programming environment for MS-DOS, FreeDOS or any DOS-based Windows (like 95, 98, ME).

FreeDOS ad-hoc module for micropython.

GitHub repository of the original source code for MS-DOS v1.25, v2.0 and v4.0, open-sourced by Microsoft.

Game development library for DOS, Windows and Linux. 4.2 version supports DOS platform.

A framework for making 2D DOS games in Lua. API based on a subset of the LÖVE API.

Marco A. Marrero's DOS VGA/hardware library implemented in assembly and Turbo Pascal.

Original source code for the DIGPAK sound drivers uploaded to GitHub by John W. Ratcliff.

Christopher Wellons's x86 real mode DOS Asteroids clone created as an entry for Lundum Dare #31.

First-person 2.5D dungeon-crawler on protected mode. Written in C++, includes software rendering, fixed point math, test coverage and sound (PC speaker, Adlib, OPL2LPT).

Flappy Bird clone written in 16 bit assembly. Not a DOS program, but a PC-Booter application instead (although it's also possible to build a COM executable for DOS).

'80s style arcade shooter written in Quickbasic. Also the very first known DOS game that supports Oculus Rift VR headset.

Descendant of the original NetHack rougelike game first released in 1987 available on multiple platforms.

Gomoku clone written in C. Works on DOS, ZX Spectrum, ZX81, ZX80, APPLE1, AS400 and Windows.

Overhead puzzle game written in C. Web version uses DOSBox ported to Emscripten to embed DOSBox into HTML5. However, the original executable is also downloadable and buildable with Open Watcom.

Tetris clone written in C. Runs on DOS, Unix/Linux, ZX Spectrum and Windows.

Tower of Hanoi puzzle game written in Turbo Pascal. Originally released in 1996.

Text-mode Pong clone written in C. Runs as PC-Booter game and under DOS.

2D top-down shooter developed by Softdisk (later becoming id Software). Supports EGA and CGA graphics. Written in Turbo Pascal and assembly.

First-person shooter in fantasy setting developed by Softdisk (later becoming id Software). Features pseudo-3D graphics with raycasting technique. Supports EGA graphics. Written in C and assembly. Compiled with Borland C++ 3.1.

Side-scrolling platform game developed by id Software. Keen Dreams is the Commander Keen game created between Keen 3 and Keen 4 (often considered "Keen 3.5"), but was not widely released. Written in C and assembly.

First sci-fi FPS/space shooter to feature entirely true 3D graphics. Written in C and assembly.

Sequel to Descent. Written in C and assembly.

Sci-fi FPS developed by id Software where you fight demons from hell on Mars. The DOS-specific code for Doom could not be published because of a dependency to the licensed DMX sound library, hence why it's cleaned up and only the Linux source is there. However, the Heretic and Hexen projects contain the original DOS code in a way where DMX-related code is removed.

Dark fantasy FPS running on id Software's Doom engine.

Indirect sequel to Heretic.

FPS developed by id Software. Features pseudo-3D graphics with raycasting technique, before Catacomb 3D and Wolfeinstein 3D. Written in C and assembly.

FPS developed by id Software set in a fully 3D world. Written in C. Compiled with DJGPP for DOS.

FPS developed by Apogee. It was developed as a follow-up to Wolfenstein 3D, but was altered and became a standalone game instead. Uses a heavily modified Wolfenstein 3D engine. Written in C.

FPS developed by id Software set in the Nazi German prison Castle Wolfenstein. Features pseudo-3D graphics with raycasting technique. Written in C and assembly.

Sequel to the original Cyberdogs. Ronny Wester, the original creator no longer maintains the website for the original C-Dogs, but multiple ports exists, including cdogs-sdl.

A TSR that emulates Sound Blaster and OPL3 in pure DOS using modern PCI-based (onboard and add-in card) sound cards. Supports both real mode and protected mode games!

A fork of SBEMU (see above), which also aims to offer Sound Blaster emulation for modern PC hardware, in both real mode and protected mode games.