- 1oom (C, GPL-2.0, mature)
- 2006-rebotted (Java, 2-clause BSD, mature)
- 2009scape (Java, Kotlin, AGPL-3.0, mature)
- 2048 Python (Python, MIT, mature)
- Abuse 1996 (C++, Lisp, Custom, Public domain, GPL-2.0, WTFPL, mature, inactive since 2016)
- Abuse (C++, Lisp, Public domain, GPL-2.0, WTFPL, mature, inactive since 2011)
- AdaDoom3 (Ada, GPL-3.0, beta)
- Afternoon Stalker (C++, GPL-2.0, mature, inactive since 2012)
- Ajax3d (JavaScript, GPL-2.0, beta, inactive since 2007)
- Aklabeth (C, GPL-2.0, mature, inactive since 2004)
- Aleph One (C++, Lua, GPL-3.0, mature)
- alive (C++, MIT, beta)
- Ambermoon.net (C#, GPL-3.0, mature)
- Angry Birds in Python (Python, MIT, mature, inactive since 2017)
- Antares (C++, LGPL-3.0, beta)
- aquastax (JavaScript, MIT, beta)
- Arashi-JS (JavaScript, GPL-2.0, beta, inactive since 2010)
- Armor Alley (JavaScript, CC-BY-NC-3.0, beta)
- Arrakis (Basic, Custom, mature, inactive since 2000)
- Artillery Duel Reloaded (Python, GPL-3.0, beta, inactive since 2012)
- Arx Libertatis (C++, GPL-3.0, mature)
- asdf (JavaScript, MIT, mature)
- AstroMenace (C++, C, GPL-3.0, mature)
- Atomiks (C, Objective-C, GPL-3.0, mature, inactive since 2015)
- Atomix (C, GPL-2.0, mature)
- Augustus (C, C++, AGPL-3.0, mature)
- Ballerburg SDL (C, GPL-3.0, mature)
- Barony (C++, GPL-3.0, mature)
- Batrachians (C++, GPL-2.0, beta, inactive since 2012)
- Battle City (C, C++, Pascal, GPL-3.0, mature, inactive since 2013)
- BetterSpades (C, GPL-3.0, beta)
- BlakedAwesomenaughts (JavaScript, PHP, MIT, beta, inactive since 2015)
- BlockOut II (C++, GPL-2.0, mature, inactive since 2014)
- Bobby (TypeScript, AGPL-3.0, mature)
- Bombic2 (C++, GPL-2.0, beta, inactive since 2010)
- Bombic (C++, Objective-C, GPL-2.0, beta, inactive since 2005)
- Bombman (Python, CC0, mature)
- BOOM: Remake (C++, Custom, mature)
- Boulder Dash (Java, MIT, mature, inactive since 2015)
- bratwurst (Lisp, GPL-2.0, mature, inactive since 2009)
- BStone (C++, GPL-2.0, mature)
- Bt Builder (C, C++, GPL-3.0, beta)
- BurgerSpace (C++, GPL-2.0, mature, inactive since 2013)
- C-Dogs SDL (C, GPL-2.0, mature)
- c64-nuclearreaction (C, Assembly, GPL-3.0, mature, inactive since 2014)
- Cadaver (C++, GPL-2.0, beta, inactive since 2009)
- CaesarIA (C++, JavaScript, C, GPL-3.0, beta)
- Cannonball (C++, MAME, beta)
- Carnage3D (C++, C, MIT, beta)
- Castle of the Winds in Elm (Elm, JavaScript, MIT, beta)
- Castle of the Winds (JavaScript, MIT, beta, inactive since 2016)
- Castle-Combat (Python, GPL-2.0, beta, inactive since 2006)
- Cataclysm: Dark Days Ahead (C++, CC-BY-SA-3.0, mature)
- CatacombGL (C++, GPL-3.0, beta)
- CatacombSDL (C, GPL-2.0, mature, inactive since 2014)
- cc94 (C++, Python, AGPL-3.0, beta)
- CCCP (C++, AGPL-3.0, beta)
- chainreaction (Java, LGPL-3.0, mature, inactive since 2017)
- Chariot (Rust, MIT, beta, inactive since 218)
- Chocolate Doom (C, GPL-2.0, mature)
- Chocolate Duke3D (C, GPL-2.0, Custom, beta, inactive since 2016)
- Chronoshift (C++, GPL-2.0, beta)
- Circus Linux! (C, GPL-2.0, mature, inactive since 2000)
- Civ2-clone (C#, GPL-3.0, beta)
- Civilization: Call To Power 2 Source Project (C, C++, Custom, mature)
- CivOne (C#, CC0, beta)
- Classic RBDoom 3 BFG (C, C++, GPL-3.0, mature)
- ClassiCube (C, 3-clause BSD, mature)
- Clumsy Bird (JavaScript, MIT, mature, inactive since 2017)
- Colditz Escape (C, GPL-3.0, mature)
- Colobot: Gold Edition (C++, GPL-3.0, mature)
- Command Series Engine (Go, GPL-2.0, mature)
- Commander Genius (C, C++, GPL-2.0, mature)
- CommandoJS (JavaScript, CoffeeScript, MIT, beta, inactive since 2012)
- CorsixTH (Lua, C++, MIT, mature)
- Cosmo-Engine (C, GPL-2.0, beta)
- Cosmore (C, Assembly, MIT, mature)
- Cosmosmash (C++, GPL-2.0, mature, inactive since 2013)
- Crack Attack! (C++, GPL-2.0, mature, inactive since 2005)
- CrappyBird (JavaScript, MIT, mature, inactive since 2017)
- Crown and Cutlass (C++, C, Custom, beta, inactive since 2009)
- CrystalQuest (JavaScript, MIT, mature, inactive since 2017)
- Cubosphere (C, C++, Lua, GPL-3.0, beta)
- Cytadela (C++, GPL-3.0, beta, inactive since 2013)
- D2X-XL (C++, Custom, GPL-2.0, mature, inactive since 2015)
- Daggerfall Unity (C#, MIT, mature)
- Danger from the Deep (C++, C, GPL-2.0, beta, inactive since 2011)
- DarkPlaces (C, GPL-2.0, mature, inactive since 2014)
- Data Storm (C, Apache-2.0, mature, inactive since 2017)
- Deathchase 3D (C, Perl, Script, GPL-2.0, mature, inactive since 2002)
- Defendguin (C, GPL-2.0, mature, inactive since 2009)
- DelverEngine (Java, Custom, mature)
- DesktopAdventures (C, LGPL-2.1, beta)
- Devilution (C, C++, Unlicense, mature)
- DevilutionX (C, C++, Unlicense, mature)
- DGEngine (C++, zlib, GPL-3.0, beta)
- dhewm3 (C, C++, GPL-3.0, mature)
- Diablerie (C#, MIT, beta)
- Digbuild (C, C++, GPL-2.0, beta, inactive since 2011)
- Digger Remastered (C, GPL-2.0, mature, inactive since 2004)
- Do It Yourself Doom With SDL (C++, MIT, beta)
- donut (C, C++, GPL-3.0, beta)
- Doom Legacy (C++, GPL-2.0, mature)
- DOOM Retro (C, C++, GPL-3.0, mature)
- DOOM-iOS (C++, C, GPL-2.0, mature, inactive since 2012)
- Doom64EX (C, C++, GPL-2.0, mature)
- Doomsday Engine (C, C++, GPL-2.0, GPL-3.0, LGPL-3.0, mature)
- Dope Wars (C, GPL-2.0, mature, inactive since 2013)
- doukutsu-rs (Rust, MIT, beta)
- dRally (Assembly, C, MIT, beta)
- DreamZZT (C, C++, GPL-2.0, beta, inactive since 2007)
- Dreerally (C, C++, Custom, beta)
- Duck Marines (Lua, zlib, mature, inactive since 2016)
- Duke3D (C, GPL-2.0, beta, inactive since 2009)
- Duke3d_w32 (C, GPL-2.0, beta, inactive since 2008)
- DukeGDX (Java, GPL-3.0, beta)
- Dune Dynasty (C, C++, GPL-2.0, mature, inactive since 2014)
- Dune II - The Maker (Java, MIT, beta)
- Dune Legacy (C++, GPL-2.0, mature)
- Dungeon Craft (C++, GPL-2.0, mature)
- Dungeon Eye (C#, GPL-3.0, beta, inactive since 2016)
- Dust Racing 2D (C, C++, GPL-3.0, mature)
- DXX-Rebirth (C, C++, Python, GPL-3.0, Custom, mature)
- Eat The Whistle (C, ?, mature, inactive since 2017)
- ECWolf (C++, GPL-2.0, LGPL-2.1, zlib, MIT, IJG, Public domain, mature)
- EDGE (C++, C, GPL-2.0, mature)
- EdisonEngine (C++, Python, LGPL-3.0, beta)
- EDuke32 (C, C++, GPL-2.0, mature)
- ElonaFoobar (C++, Lua, MIT, mature)
- Enduro tribute (JavaScript, MIT, mature)
- engge (C++, MIT, beta)
- Enigma (C, C++, GPL-2.0, mature)
- EnTT Pacman (C, C++, MIT, mature)
- erampage (C, GPL-2.0, beta, inactive since 2015)
- ET: Legacy (C, C++, Lua, GPL-3.0, mature)
- Executive Man (JavaScript, Custom, mature, inactive since 2017)
- Exult (C++, GPL-2.0, mature)
- ezQuake (C, C++, GPL-2.0, mature)
- F-1 Spirit (C++, ?, beta, inactive since 2009)
- Falcon's Eye (C, NetHack General Public License, mature, inactive since 2004)
- Falltergeist (C++, GPL-3.0, beta)
- Fanwor (C, GPL-2.0, mature)
- Fitzquake (C, GPL-2.0, beta, inactive since 2009)
- Flappy Cow (Java, MIT, mature)
- Fluid Table Tennis (JavaScript, MIT, mature, inactive since 2013)
- fonline (C, C++, C#, GPL-3.0, beta)
- Forsaken (C, C++, GPL-2.0, Proprietary, beta, inactive since 2013)
- FQuake3 (F#, C, GPL-2.0, beta, inactive since 2014)
- Free Allegiance (C++, MIT, mature)
- Free Heroes 2 (C++, GPL-2.0, beta, inactive since 2015)
- Free in the Dark (engine) (C, C++, GPL-2.0, beta)
- freeablo (C++, GPL-3.0, beta)
- freeaoe (C++, GPL-3.0, beta)
- FreeBlocks (C, Java, GPL-3.0, beta, inactive since 2015)
- Freeciv Alpha Centauri project (C, GPL-2.0, beta, inactive since 2003)
- FreeCol (Java, GPL-2.0, mature)
- FreeCS (QuakeC, GPL-2.0, mature)
- Freedoom (None, Python, None, beta)
- freegish (C, GPL-2.0, beta, inactive since 2017)
- Freekick 3 (C++, Python, GPL-3.0, mature, inactive since 2015)
- FreeLords (Java, GPL-2.0, beta, inactive since 2017)
- Freenukum (C, GPL-3.0, beta, inactive since 2009)
- FreeOrion (C++, Python, GPL-2.0, beta)
- FreePrince (C, GPL-2.0, beta, inactive since 2011)
- FreeRails (Java, C++, GPL-2.0, beta, inactive since 2008)
- FreeRCT (C++, GPL-2.0, beta, inactive since 2016)
- Freeserf.net (C#, GPL-3.0, mature)
- Freeserf (C, C++, GPL-3.0, mature)
- FreeSiege (C++, GPL-3.0, beta)
- FreeSims (C#, MPL-2.0, beta)
- FreeSO (C#, MPL-2.0, beta)
- FreeSpace 2 Source Code Project (C, C++, Unlicense, mature)
- Freestars (C++, GPL-2.0, beta, inactive since 2008)
- FreeSynd (C++, GPL-2.0, beta, inactive since 2017)
- Frets on Fire X (Python, GPL-2.0, mature)
- Frets on Fire (Python, GPL-2.0, mature, inactive since 2008)
- Froggix (Python, GPL-3.0, beta, inactive since 2009)
- Galaxy Forces V2 (C++, Public domain, mature)
- GDash (C++, MIT, beta)
- GemRB (C++, Python, GPL-2.0, mature)
- ges-code (C, C++, GPL-3.0, mature)
- Ghostly (C++, GPL-3.0, mature, inactive since 2016)
- Gift Grabber (JavaScript, Apache-2.0, mature)
- Gigalomania (C++, GPL-2.0, mature)
- glPortal (C++, zlib, beta)
- GLSpeed (Pascal, C, GPL-2.0, mature)
- Gnomescroll (C, C++, Python, GPL-3.0, beta, inactive since 2013)
- GNU FreeDink (C, GPL-3.0, mature, inactive since 2012)
- GoldenEye: Source (C++, C, GPL-3.0, mature, inactive since 2018)
- Gorc (C++, Apache-2.0, beta)
- Gorillas-rs (Rust, MIT, beta)
- Gorillas (Objective-C, JavaScript, Java Research License, mature, inactive since 2014)
- Gottet (C++, GPL-3.0, mature)
- Greenius' Civil War (C++, C, GPL-2.0, beta, inactive since 2001)
- Greentwip's Harvest Moon (C#, GPL-3.0, beta)
- Griefly (C++, Go, Python, MIT, beta)
- GUSANOS (C++, GPL-2.0, beta, inactive since 2006)
- GZDoom (C, C++, GPL-3.0, mature)
- Hammer of Thyrion (C, GPL-2.0, mature)
- Hardwar (C++, GPL-3.0, beta, inactive since 2015)
- Head over Heels (C++, GPL-3.0, mature)
- Heart of the Alien (C, GPL-2.0, beta, inactive since 2005)
- Hematite (Rust, MIT, beta)
- Hocoslamfy (C, C++, GPL-2.0, beta, inactive since 2016)
- Hopson-Arcade (C++, GPL-3.0, mature)
- HoverRace (C++, Custom, mature, inactive since 2016)
- Hovertank3D (C++, Assembly, GPL-2.0, mature, inactive since 2014)
- HTML5 Pacman (JavaScript, WTFPL, mature, inactive since 2013)
- I Have No Tomatoes (C++, zlib, mature, inactive since 2004)
- Ice Breaker (C, GPL-2.0, mature, inactive since 2003)
- Iceball (C, Lua, GPL-3.0, inactive since 2017)
- Inertia Blast (C, GPL-2.0, mature)
- Inexor (C++, JavaScript, zlib, beta, inactive since 2018)
- ioquake3 (C, GPL-2.0, mature)
- iortcw (C, C++, GPL-3.0, mature)
- Iris2 (C, C++, Lua, GPL-3.0, beta, inactive since 2017)
- Ironseed (Pascal, GPL-3.0, mature, inactive since 2013)
- irrlamb (C, C++, GPL-3.0, mature)
- Jagged Alliance 2 Stracciatella (C, C++, Custom, mature)
- Jake2 (Java, GPL-2.0, beta, inactive since 2006)
- javascript-E.T. (JavaScript, Assembly, MIT, beta, inactive since 2017)
- Jazz² Resurrection (C#, JavaScript, GPL-3.0, mature)
- JediAcademyLinux (C++, GPL-2.0, beta, inactive since 2017)
- JediOutcastLinux (C, C++, GPL-2.0, mature)
- Jet-Story (Assembly, C, C++, MIT, beta)
- jewelthief (Java, GPL-3.0, mature, inactive since 2016)
- JFDuke3D (C, GPL-2.0, beta, inactive since 2005)
- JonoF's Shadow Warrior Port (JFSW) (C, GPL-2.0, beta, inactive since 2005)
- JSettlers (Java, GPL-3.0, mature)
- jsFO (JavaScript, Python, Apache-2.0, beta, inactive since 2017)
- Julius (C, C++, AGPL-3.0, mature)
- Jump'n'Bump (C, GPL-2.0, mature, inactive since 2004)
- Just another Tetris™ clone (Java, WTFPL, mature, inactive since 2017)
- KaM Remake (Pascal, AGPL-3.0, mature)
- KAtomic (C++, GPL-2.0, mature)
- Keen Dreams (C, Assembly, C++, GPL-2.0, mature, inactive since 2014)
- KGoldrunner (C++, GPL-2.0, mature)
- KittenMaxit (Java, MIT, beta)
- KnightOfWor (Java, GPL-3.0, beta, inactive since 2015)
- Knights (C++, GPL-3.0, beta, inactive since 2014)
- Krystal Drop (C++, GPL-2.0, beta, inactive since 2004)
- l-echo (C++, GPL-3.0, beta, inactive since 2016)
- ladder (Go, MIT, beta, inactive since 2016)
- Ladder (Java, GPL-2.0, mature, inactive since 2005)
- LastTry (Java, MIT, beta, inactive since 2017)
- LBA2 Remake (TypeScript, MIT, beta)
- LGeneral (C, GPL-2.0, mature, inactive since 2017)
- Librelancer (C, C#, MIT, beta)
- LibreQuake (Python, 3-clause BSD, beta)
- Lionheart Remake (Java, GPL-3.0, beta, inactive since 2018)
- Lords of the Fey (JavaScript, AGPL-3.0, beta, inactive since 2018)
- Lose Your Marbles (JavaScript, MIT, mature, inactive since 2014)
- lttp-phaser (TypeScript, JavaScript, MIT, beta, inactive since 2016)
- Lugaru (C++, GPL-2.0, mature)
- LZWolf (C++, 3-clause BSD, mature)
- M.E.W.L. (C++, GPL-2.0, beta, inactive since 2015)
- Maelstrom (C, C++, GPL-2.0, mature, inactive since 2002)
- MafiaUnity (C#, Apache-2.0, beta, inactive since 2020)
- ManiaDrive (PHP, ?, mature, inactive since 2008)
- Manic Digger (C#, Public domain, Unlicense, mature, inactive since 2017)
- Mari0 (Lua, MIT, mature, inactive since 2012)
- Maxit (C++, 3-clause BSD, mature, inactive since 2014)
- mc2 (C++, GPL-3.0, beta)
- Mechanized Assault & eXploration Reloaded (C++, C, GPL-2.0, beta)
- MechCommander 2 Omnitech (C++, MS-PL, beta, inactive since 2013)
- Mega Mario (C++, LGPL-2.1, mature, inactive since 2012)
- MegaGlest (C, C++, GPL-3.0, mature)
- Memoria (C#, MIT, mature)
- Metaforce (C, C++, MIT, beta)
- Mice Men: Remix (Java, LGPL-3.0, mature, inactive since 2016)
- Microracers (C, C++, GPL-2.0, beta, inactive since 2005)
- Minesweeper (in C) (C, 3-clause BSD, beta, inactive since 2015)
- Minesweeper.Zone (JavaScript, PHP, MIT, mature)
- Minetest (C, C++, Lua, LGPL-2.1, mature)
- Mininim (C, GPL-3.0, beta, inactive since 2017)
- Mirror Magic (C, GPL-2.0, mature)
- mk.js (JavaScript, MIT, beta)
- Mocha Doom (Java, GPL-3.0, beta, inactive since 2012)
- Monsters and Mushrooms (Python, GPL-2.0, mature, inactive since 2010)
- Moonbase Assault (Java, MIT, beta, inactive since 2019)
- Morpheus Web Remake (JavaScript, MIT, beta)
- movbizz (PHP, JavaScript, MIT, beta, inactive since 2015)
- Mr.Boom (C++, C, MIT, mature)
- Nanosaur Source Port (C, CC-BY-NC-SA-4.0, mature)
- NBlood (C, C++, Lua, GPL-2.0, mature)
- NEO-RAW (C++, GPL-2.0, mature, inactive since 2020)
- Netacka (C, MIT, mature)
- NFSIISE (C, MIT, mature)
- Nighthawk (C++, C, GPL-2.0, mature, inactive since 2004)
- NLarn (C, Lua, GPL-3.0, mature)
- NorseWorld: Ragnarok (C#, GPL-3.0, beta)
- NStars! (C#, ?, beta, inactive since 2004)
- NullpoMino (Java, 3-clause BSD, mature)
- Nuvie (C, C++, Lua, GPL-2.0, beta, inactive since 2018)
- NXEngine-evo (C++, C, GPL-3.0, mature)
- NXEngine (C, C++, GPL-3.0, mature)
- Odamex (C, C++, GPL-2.0, beta)
- Omnispeak (C, GPL-2.0, mature)
- One Hour One Life (C, C++, PHP, Public domain, mature)
- One Way To Go (Lua, GPL-3.0, mature, inactive since 2011)
- Open Apocalypse (C++, MIT, beta)
- Open Cube (C++, C, zlib, beta, inactive since 2017)
- Open Fodder (C, C++, GPL-3.0, mature)
- Open Fortress (C++, CC-BY-NC-SA-4.0, Custom, beta)
- Open Horizon (C++, MIT, beta)
- Open Imperium Galactica (Java, LGPL-3.0, mature)
- Open Jumpgate (C++, GPL-2.0, beta, inactive since 2017)
- Open Meridian (C, C++, GPL-2.0, mature)
- Open Panzer (JavaScript, GPL-2.0, mature)
- Open Rodent's Revenge (C++, MIT, beta, inactive since 2018)
- Open RSC (Java, C++, C, Objective-C, AGPL-3.0, mature)
- Open Syobon Action (C++, ?, beta, inactive since 2011)
- Open Valley (C++, CC-BY-NC-SA-4.0, beta)
- openage (C++, Python, GPL-3.0, beta)
- OpenArena (C, GPL-2.0, mature, inactive since 2012)
- openblack (C, C++, GPL-3.0, beta)
- openc2e (C, C++, LGPL-2.1, beta)
- OpenClaw (C++, GPL-3.0, mature)
- OpenClonk (C, C++, ISC, mature)
- OpenCrystalCaves (C++, MIT, beta, inactive since 2017)
- OpenDiablo2 (Go, GPL-3.0, mature)
- openDOW (C, GPL-3.0, beta)
- OpenDUNE (C, GPL-2.0, mature)
- OpenEtG (JavaScript, MIT, beta)
- OpenFly (C, GPL-2.0, beta, inactive since 2001)
- OpenGGS (C++, GPL-2.0, beta, inactive since 2017)
- OpenGL Test Drive Remake (C, C++, GPL-3.0, mature, inactive since 2015)
- Openglad (C++, GPL-2.0, mature, inactive since 2004)
- OpenGothic (C++, MIT, beta)
- OpenHoW (C, C++, GPL-3.0, beta)
- OpenJazz (C++, GPL-2.0, beta)
- OpenJK (C, C++, GPL-2.0, beta)
- OpenKeeper (Java, GPL-3.0, beta)
- OpenKrush (C#, GPL-3.0, beta)
- OpenLara (C++, C, 2-clause BSD, mature)
- OpenLiero (C++, C, Custom, mature, inactive since 2015)
- OpenLieroX (C++, LGPL-2.0, mature)
- OpenLoco (C++, MIT, mature)
- OpenMC2 (C++, GPL-3.0, beta, inactive since 2018)
- OpenMOO2 (Python, GPL-2.0, beta, inactive since 2011)
- OpenMW for Android (Kotlin, Java, GPL-3.0, mature)
- OpenMW (C++, GPL-3.0, mature)
- OpenNFS (C, C++, MIT, beta)
- OpenNotrium (C++, GPL-3.0, beta)
- OpenOMF (C, C++, MIT, beta)
- OpenRA (C#, GPL-3.0, mature)
- OpenRaider (C, C++, GPL-2.0, beta, inactive since 2015)
- OpenRCT2 (C++, GPL-3.0, mature)
- OpenRoads (TypeScript, JavaScript, MIT, mature, inactive since 2014)
- OpenRW (C, C++, GPL-3.0, beta)
- OpenSA (C#, Lua, GPL-3.0, mature)
- OpenSC2K (JavaScript, GPL-3.0, beta)
- OpenSkyscraper (C++, GPL-2.0, beta)
- OpenSpades (C, C++, AngelScript, GPL-3.0, beta)
- OpenSR (C++, GPL-3.0, beta, inactive since 2017)
- OpenSupaplex (C, GPL-3.0, mature)
- OpenSWE1R (C, C++, GPL-2.0, beta)
- OpenTESArena (C++, MIT, beta)
- OpenTitus (C, GPL-3.0, beta, inactive since 2014)
- OpenTomb (C, C++, Lua, LGPL-3.0, beta)
- OpenTriad (Java, GPL-3.0, beta, inactive since 2017)
- OpenTTD (C++, GPL-2.0, mature)
- OpenTyrian (C, GPL-2.0, beta, inactive since 2018)
- OpenVIII (C#, MIT, beta)
- OpenXcom (C++, GPL-3.0, mature)
- OpenXRay (C++, Lua, ?, mature)
- OPMon (C++, GPL-3.0, beta)
- Orbium (JavaScript, GPL-2.0, mature, inactive since 2018)
- orona (CoffeeScript, GPL-2.0, beta, inactive since 2012)
- Ostrich Riders (C++, GPL-3.0, beta)
- Outpost HD (C++, 3-clause BSD, beta)
- pacman-canvas (JavaScript, CC-BY-SA-4.0, mature, inactive since 2018)
- Panel Attack (Lua, zlib, beta)
- Pang Zero (Perl, GPL-2.0, beta, inactive since 2007)
- PARPG (Python, GPL-3.0, beta, inactive since 2012)
- Pathological (Python, Script, GPL-2.0, beta, inactive since 2003)
- PCExhumed (C++, Custom, beta)
- Pentagram (C++, GPL-2.0, beta, inactive since 2018)
- POSTAL 1 Open Source (C++, GPL-2.0, beta, inactive since 2018)
- Powerslave EX (C, C++, GPL-3.0, beta, inactive since 2017)
- PowerslaveGDX (Java, Custom, beta)
- Powerslide remake (C++, MIT, beta)
- pq2 (C++, GPL-3.0, mature)
- PrBoom+ (C, GPL-2.0, mature, inactive since 2016)
- Prescription Wars (ColdFusion, JavaScript, GPL-3.0, mature, inactive since 2016)
- Prince-Monogame (C#, GPL-2.0, beta)
- Privateer - Gemini Gold (C++, GPL-2.0, mature, inactive since 2012)
- progress-quest (C++, Python, MIT, mature)
- Project Carrot (C++, MIT, beta, inactive since 2017)
- Project Dollhouse (C#, MPL-2.0, beta)
- ProQuake 4 (C, GPL-2.0, mature, inactive since 2018)
- Pushover (C++, C, Lua, GPL-3.0, beta, inactive since 2018)
- pycraft (C, Python, GPL-2.0, mature, inactive since 2018)
- pyskool (Python, GPL-3.0, mature)
- Python Kye (Python, GPL-2.0, mature, inactive since 2010)
- Q-Gears (C, C++, GPL-2.0, beta, inactive since 2015)
- Quake3e (C, GPL-2.0, beta)
- QuakeJS (JavaScript, MIT, mature)
- QuakeSpasm (C, GPL-2.0, mature)
- Rabbit Escape (Java, GPL-2.0, mature)
- Race Into Space (C, C++, GPL-2.0, mature)
- RAD (Pascal, C, GPL-2.0, mature)
- Raptor: Call of the Shadows (C, GPL-3.0, beta)
- Raze (C++, GPL-2.0, mature)
- RBDOOM-3-BFG (C, C++, GPL-3.0, mature)
- re-private-eye (Python, 2-clause BSD, beta)
- Reconstruction of Super ZZT (Pascal, MIT, mature)
- Reconstruction of ZZT (Pascal, MIT, mature)
- RedneckGDX (Java, Custom, beta)
- Rednukem (C++, Custom, beta)
- REDriver2 (C++, C, MIT, beta)
- Reflection Keen (C, Lua, GPL-2.0, mature)
- REGoth (C++, GPL-3.0, MIT, mature)
- remc2 (C, GPL-3.0, mature)
- Remixed Dungeon (Java, GPL-3.0, mature)
- reone (C++, GPL-3.0, beta)
- ReQbert (JavaScript, GPL-3.0, beta)
- Rescue! Max (Java, GPL-3.0, beta, inactive since 2013)
- ResidualVM (C++, GPL-2.0, beta)
- Return of Dr. Destructo (C++, MIT, mature, inactive since 2015)
- Return to the Roots (C++, GPL-3.0, mature)
- RickyD (C++, GPL-2.0, beta)
- Rigel Engine (C++, GPL-2.0, beta)
- Riiablo (Java, Apache-2.0, beta)
- Rise of the Triad for Linux (C, GPL-2.0, mature, inactive since 2012)
- Robot Redemption (C++, CC-BY-NC-SA-4.0, GPL-2.0, mature, inactive since 2014)
- rock-raiders-remake (JavaScript, MIT, beta)
- Rockbot (C++, GPL-2.0, mature)
- Rocks'n'Diamonds (C, GPL-2.0, mature)
- Rogue Clone IV (C, 3-clause BSD, mature, inactive since 2006)
- Rot Magus (JavaScript, Apache-2.0, CC0, beta)
- Roton (C#, ISC, beta, inactive since 2019)
- Rott94 (C, C++, GPL-2.0, beta)
- rottexpr (C, GPL-2.0, beta)
- RPG-X (C, GPL-2.0, mature, inactive since 2015)
- RuneLite (Java, 2-clause BSD, mature)
- RuZZT (Rust, MIT, beta)
- Ryzom Core (C++, PHP, AGPL-3.0, mature)
- SanAndreasUnity (C#, MIT, mature)
- Scorched Moon (Python, GPL-3.0, beta)
- ScummVM (C++, GPL-2.0, mature)
- SDL Asylum (C, GPL-3.0, mature, inactive since 2009)
- SDL Bomber (C, GPL-2.0, mature, inactive since 2012)
- SDL Sopwith (C, C++, GPL-2.0, mature, inactive since 2014)
- SDLPoP (C, GPL-3.0, mature)
- Secret Maryo Chronicles (C++, GPL-3.0, mature, inactive since 2009)
- sensitive-js (JavaScript, Custom, beta, inactive since 2017)
- Settlers III remake (Java, MIT, beta)
- Seven Kingdoms: Ancient Adversaries (C++, GPL-2.0, mature)
- sfall (C++, C, GPL-3.0, mature)
- shadow-of-the-beast-html5 (JavaScript, Apache-2.0, beta, inactive since 2017)
- Shadowgrounds (C++, Custom, beta, inactive since 2017)
- Shockolate (C, GPL-3.0, beta)
- Shotgun Debugger (C++, GPL-2.0, mature, inactive since 2005)
- Siege of Avalon : Open Source (Pascal, Custom, beta, inactive since 2011)
- Simitone (C#, MPL-2.0, beta)
- Simon Tatham's Portable Puzzle Collection (C, MIT, mature)
- Sine (C, C++, MIT, beta)
- Skifree-HTML5-clone (JavaScript, GPL-3.0, beta, inactive since 2011)
- skifree.js (JavaScript, MIT, mature, inactive since 2016)
- Slot-Racers (C, C++, GPL-3.0, mature, inactive since 2008)
- snake (Java, WTFPL, mature, inactive since 2017)
- Solarus (C, C++, Lua, GPL-3.0, mature)
- SolarWolf (Python, LGPL-2.1, mature, inactive since 2004)
- Sopwith 3 (C, C++, Objective-C, GPL-2.0, beta, inactive since 2003)
- Sourcehold (C++, MIT, beta)
- Space Nerds In Space (C, Lua, GPL-2.0, beta)
- SpaceCadetPinball (C++, MIT, mature)
- splexhd (C++, GPL-2.0, beta, inactive since 2012)
- Spring (C++, C, Lua, GPL-2.0, mature)
- SS13 Remake (C#, GPL-3.0, beta, inactive since 2015)
- Star Ruler 2 (C, C++, MIT, mature)
- star-control2 (C, C++, MIT, mature)
- Star-Wars-III (Python, GPL-2.0, mature, inactive since 2014)
- Stargus (C++, Lua, GPL-2.0, beta, inactive since 2010)
- starshatter-open (C++, 3-clause BSD, beta, inactive since 2015)
- Strife: Veteran Edition (C, C++, Objective-C, GPL-3.0, beta, inactive since 2016)
- SunDog Resurrection (Java, Python, Artistic License-1.0, beta)
- sundog (C, C++, Python, MIT, beta)
- Supaxl (JavaScript, MIT, mature)
- Super Methane Brothers for Wii and GameCube (C++, GPL-2.0, beta, inactive since 2018)
- Super Methane Brothers (C++, GPL-2.0, mature, inactive since 2011)
- Supercars III (Java, ?, mature, inactive since 2014)
- SuperFoulEgg (Objective-C, C, MIT, mature, inactive since 2014)
- Survivor (JavaScript, CC-BY-NC-3.0, mature)
- SWP (C, C++, GPL-2.0, mature)
- Syndicate Wars Port (C, GPL-3.0, beta, inactive since 2010)
- Taisei Project (C, Python, MIT, mature)
- Tapir (C, Ruby, Apache-2.0, MIT, beta, inactive since 2017)
- TekwarGDX (Java, Custom, beta)
- Terasology (Java, Apache-2.0, mature)
- terrarium (C++, Script, GPL-2.0, beta)
- TES3MP (C++, GPL-3.0, beta)
- Tetris (in C and NCURSES) (C, 3-clause BSD, mature)
- The Bub's Brothers (Python, C, MIT, mature, inactive since 2013)
- The Castles of Dr. Creep (C++, Script, GPL-3.0, mature)
- The Eternity Engine (C, C++, GPL-3.0, mature)
- The Force Engine (C++, GPL-2.0, beta)
- The Secret Chronicles of Dr. M. (C++, GPL-3.0, mature)
- The Ur-Quan Masters (C, GPL-2.0, mature, inactive since 2011)
- The-Trail (Java, MIT, Apache-2.0, beta, inactive since 2018)
- Theme Park Builder 3D CAD (C++, GPL-3.0, beta, inactive since 2013)
- thiefcatcher (C++, GPL-3.0, beta)
- Thrust (C, GPL-2.0, beta, inactive since 2006)
- Thyme (C, C++, GPL-2.0, beta)
- Tile World (C, GPL-2.0, mature, inactive since 2015)
- Tiny Wings (Objective-C, C, C++, MIT, beta)
- TOMB5 (C, C++, MIT, beta)
- Toppler (C++, GPL-2.0, mature, inactive since 2012)
- Total Annihilation 3D (C++, C, Lua, GPL-2.0, beta, inactive since 2017)
- Tower Toppler (C++, GPL-2.0, mature, inactive since 2012)
- Trackballs (C++, Scheme, GPL-2.0, mature)
- Train (Java, 3-clause BSD, beta)
- Transfusion (C, GPL-2.0, beta, inactive since 2007)
- Tremfusion (C, GPL-2.0, mature, inactive since 2009)
- TrueCraft (C#, MIT, beta, inactive since 2018)
- Tumbly Towers (Java, MIT, beta, inactive since 2017)
- TurokEX (C++, C, GPL-2.0, beta, inactive since 2014)
- Tuxemon (Python, GPL-3.0, beta)
- TVTower (BlitzMax, Lua, Custom, mature)
- twin-e (C, GPL-2.0, beta, inactive since 2015)
- TwinEngine (C, GPL-2.0, mature, inactive since 2015)
- Tyger (Python, ?, beta, inactive since 2016)
- Tyrian Remake (Java, GPL-2.0, beta)
- TyrQuake (C, GPL-2.0, beta)
- UA_source (C++, GPL-2.0, beta)
- UFO2000 (C, C++, Lua, GPL-2.0, mature, inactive since 2012)
- Ultima 5 Redux (C#, MIT, beta)
- Ultimate Stunts (C++, GPL-2.0, beta, inactive since 2013)
- UltraStar Deluxe (Pascal, GPL-2.0, mature)
- UltraStar Play (C#, MIT, beta)
- uMario (C++, GPL-2.0, beta, inactive since 2016)
- UnCiv (Kotlin, MPL-2.0, beta)
- UnderworldExporter (C#, C++, MIT, mature)
- uninvited (C, C++, Artistic License-2.0, beta, inactive since 2016)
- Vangers (C++, GPL-3.0, mature)
- Vanilla-Conquer (C, C++, Assembly, GPL-3.0, mature)
- VCMI (C++, GPL-2.0, mature)
- Vectoroids (C, GPL-2.0, mature, inactive since 2002)
- Veraball (GDScript, MIT, beta, inactive since 2016)
- Vertigo (C, GPL-2.0, beta, inactive since 2002)
- Violetland (C++, GPL-3.0, beta)
- Visual Pinball (C++, MAME, mature)
- vitetris (C, 2-clause BSD, beta)
- vkQuake (C, C++, GPL-2.0, mature)
- Vorton (C, GPL-3.0, beta, inactive since 2004)
- Voxelands (C++, C, GPL-3.0, beta)
- VVVVVV (ActionScript, C++, Custom, mature)
- War1 (C, zlib, beta)
- warcraft-remake (Java, GPL-2.0, beta)
- Wargus (C++, Lua, C, GPL-2.0, mature)
- Wario-Land-3 (Python, MIT, beta, inactive since 2018)
- Warzone 2100 (C++, GPL-2.0, mature)
- WAtomic (Pascal, GPL-2.0, mature, inactive since 2005)
- WebFun (TypeScript, MIT, beta)
- WebQuake (JavaScript, GPL-2.0, mature, inactive since 2019)
- Witch Blast (C++, GPL-3.0, beta, inactive since 2015)
- WitchavenGDX (Java, Custom, beta)
- Wizardry Legacy (C++, C, Objective-C, GPL-3.0, beta, inactive since 2018)
- Wizards Magic (Python, GPL-2.0, mature, inactive since 2012)
- Wizznic! (C, GPL-3.0, beta, inactive since 2016)
- wkbre (C++, C, GPL-3.0, beta)
- Wolf3dX (C#, GPL-2.0, beta)
- Wolf4SDL (C, GPL-2.0, mature)
- World of Might and Magic (C++, LGPL-3.0, beta)
- wxLaserTank (C++, GPL-2.0, mature, inactive since 2009)
- X-Moto (C++, GPL-2.0, mature, inactive since 2014)
- Xargon (C++, GPL-3.0, mature, inactive since 2015)
- xBaK (C++, GPL-3.0, beta, inactive since 2013)
- xDuke (C, GPL-2.0, beta, inactive since 2010)
- xoreos (C++, GPL-3.0, beta)
- XPilot NG (C, GPL-2.0, mature, inactive since 2010)
- XScavenger (C, GPL-2.0, mature, inactive since 2015)
- XSwing Plus (Java, GPL-3.0, beta, inactive since 2010)
- xu4 (C++, GPL-2.0, mature, inactive since 2016)
- Yamagi Quake II (C, GPL-2.0, mature)
- YKnytt (C#, MIT, beta)
- YSoccer (Java, GPL-2.0, mature)
- Zatacka X (C, GPL-3.0, beta)
- Zaz (C++, GPL-3.0, beta, inactive since 2010)
- ZDoom (C, C++, ZenScript, GPL-3.0, mature)
- Zed Online (C++, ?, mature)
- Zod Engine (C++, ?, mature, inactive since 2018)
- zorkClone (Java, Apache-2.0, beta)
- zztgo (Go, MIT, beta)