- 0 A.D. (C, C++, JavaScript, GPL-2.0, beta)
- 2009scape (Java, Kotlin, AGPL-3.0, mature)
- 3D Pong (C, GPL-2.0, beta, inactive since 2004)
- 4D Maze Game (Java, Public domain, mature, inactive since 2008)
- 4D-TRIS (C, GPL-2.0, mature, inactive since 2012)
- Abe's Amazing Adventure (C, GPL-2.0, mature, inactive since 2005)
- AdaGate (Ada, GPL-3.0, mature)
- Aleph One (C++, Lua, GPL-3.0, mature)
- Alex the Allegator 4 (C, GPL-2.0, mature, inactive since 2003)
- Ambermoon.net (C#, GPL-3.0, mature)
- AntiChess (Java, MIT, beta, inactive since 2003)
- Armory (Haxe, Python, zlib, mature)
- AssaultCube (C, C++, Custom, mature, inactive since 2018)
- Augustus (C, C++, AGPL-3.0, mature)
- Azimuth (C, GPL-3.0, mature)
- Battle Tanks (C++, GPL-2.0, mature, inactive since 2009)
- Belote (Java, GPL-3.0, beta)
- Biniax (C, zlib, mature, inactive since 2012)
- Bitfighter (C, C++, GPL-2.0, mature)
- Black Shades (C, GPL-3.0, mature)
- Bladecoder Adventure Engine (Java, Apache-2.0, mature)
- Blitwizard (C, C++, Lua, zlib, beta, inactive since 2015)
- Blobby Volley 2 (C++, GPL-2.0, mature, inactive since 2017)
- Bombic (C++, Objective-C, GPL-2.0, beta, inactive since 2005)
- Brain Workshop (Python, GPL-2.0, mature, inactive since 2011)
- Brogue (C, AGPL-3.0, mature)
- BZFlag (C++, LGPL-2.1, MPL-2.0, mature)
- C-Dogs SDL (C, GPL-2.0, mature)
- CaesarIA (C++, JavaScript, C, GPL-3.0, beta)
- Cartographer (GDScript, Apache-2.0, mature)
- Cataclysm: Dark Days Ahead (C++, CC-BY-SA-3.0, mature)
- CaveExpress (C, JavaScript, GPL-3.0, mature)
- CETech (C, C++, CC0, beta)
- Chocolate Doom (C, GPL-2.0, mature)
- Chunk Stories (Kotlin, Java, LGPL-3.0, beta)
- Circus Linux! (C, GPL-2.0, mature, inactive since 2000)
- Citybound (Rust, JavaScript, AGPL-3.0, beta)
- ClassiCube (C, 3-clause BSD, mature)
- Colditz Escape (C, GPL-3.0, mature)
- CoTerminalApps (Ada, GPL-3.0, mature)
- Craft (C, Python, MIT, mature, inactive since 2017)
- CrossUO (C, C++, GPL-3.0, mature)
- Crystal Space 3D SDK (C, C++, LGPL-2.1, mature, inactive since 2015)
- Cube 2: Sauerbraten (C, C++, Custom, mature, inactive since 2020)
- Cube (C, C++, Custom, mature, inactive since 2005)
- Cultivation (C++, Public domain, mature, inactive since 2010)
- 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)
- DarkPlaces (C, GPL-2.0, mature, inactive since 2014)
- Dave Gnukem (C++, GPL-2.0, mature)
- DDraceNetwork (C, C++, zlib, mature)
- DeSmuME (C, C++, GPL-2.0, mature, inactive since 2015)
- Destination Sol (Java, Apache-2.0, mature)
- Dethrace (C, GPL-3.0, beta)
- dhewm3 (C, C++, GPL-3.0, mature)
- Digital: A Love Story (Ren'Py, Python, CC-BY-NC-SA-3.0, mature)
- dim3 (C, MIT, beta, inactive since 2014)
- Domination (Java, GPL-3.0, mature)
- Doom Legacy (C++, GPL-2.0, mature)
- Doom64EX (C, C++, GPL-2.0, mature)
- Doomsday Engine (C, C++, GPL-2.0, GPL-3.0, LGPL-3.0, mature)
- DreamChess (C, GPL-3.0, beta)
- DRL (Lua, Pascal, GPL-2.0, mature)
- Duck Marines (Lua, zlib, mature, inactive since 2016)
- Dungeon (Java, 3-clause BSD, mature)
- DwarfCorp (C#, MIT, mature)
- Eat The Whistle (C, ?, mature, inactive since 2017)
- ECWolf (C++, GPL-2.0, LGPL-2.1, zlib, MIT, IJG, Public domain, mature)
- ElonaFoobar (C++, Lua, MIT, mature)
- Emilia Pinball (C++, GPL-2.0, beta)
- Enigma (C, C++, GPL-2.0, mature)
- Escape Towards The Unknown (C, GPL-2.0, beta, inactive since 2016)
- Esenthel Engine (C, C++, Custom, beta)
- ET: Legacy (C, C++, Lua, GPL-3.0, mature)
- Etterna (C, C++, Lua, MIT, beta)
- ezEngine (C++, JavaScript, MIT, mature)
- ezQuake (C, C++, GPL-2.0, mature)
- F-1 Spirit (C++, ?, beta, inactive since 2009)
- Fallout 2 Community Edition (C++, Custom, mature)
- Fish Fillets - Next Generation (C++, GPL-2.0, mature)
- Flare (C++, Java, Python, GPL-3.0, mature)
- FlightGear (C++, GPL-2.0, mature)
- flixel-gdx (Java, 3-clause BSD, beta, inactive since 2017)
- FLTK Recycling Game! (C++, LGPL-2.1, mature, inactive since 2014)
- Free Mars (Java, GPL-3.0, mature)
- freeablo (C++, GPL-3.0, beta)
- Freedoom (None, Python, None, beta)
- FreeSpace 2 Source Code Project (C, C++, Unlicense, mature)
- Frets on Fire (Python, GPL-2.0, mature, inactive since 2008)
- Frozen Bubble (Perl, C++, GPL-2.0, mature, inactive since 2012)
- FTEQW (C, GPL-2.0, mature)
- Game Editor (C, C++, GPL-3.0, mature, inactive since 2014)
- GameCake (C, C++, Lua, MIT, mature)
- gamekit (C++, C, zlib, mature, inactive since 2015)
- GamePlay (C++, C, Apache-2.0, mature, inactive since 2016)
- GBDK (C, Assembly, C++, MIT, mature)
- GCompris (C, Python, GPL-3.0, mature)
- Gem Drop X (C, GPL-2.0, beta, inactive since 2002)
- Gideros (C, C++, Lua, ?, mature)
- GL-117 (C++, GPL-2.0, mature, inactive since 2005)
- GLtron (C, ?, beta, inactive since 2017)
- GNU Chess (C++, GPL-3.0, mature, inactive since 2017)
- GNU FreeDink (C, GPL-3.0, mature, inactive since 2012)
- GNU Go (C, GPL-3.0, mature, inactive since 2011)
- Golly (C++, Java, GPL-2.0, mature)
- Gottet (C++, GPL-3.0, mature)
- Goxel (C, C++, GPL-3.0, beta)
- GPL Arcade Volleyball (C++, GPL-2.0, beta, inactive since 2006)
- Gravitation (C++, Public domain, mature, inactive since 2008)
- Grobots (C++, GPL-2.0, mature, inactive since 2014)
- GZDoom (C, C++, GPL-3.0, mature)
- Hammer of Thyrion (C, GPL-2.0, mature)
- Hardwar (C++, GPL-3.0, beta, inactive since 2015)
- Harmonist: Dayoriah Clan Infiltration (Go, ISC, beta)
- HaxePunk (Haxe, MIT, mature)
- HoDoKu (Java, GPL-3.0, mature, inactive since 2013)
- HyperRogue (C++, GPL-2.0, mature)
- I Have No Tomatoes (C++, zlib, mature, inactive since 2004)
- Infinite Mario Bros (Java, 3-clause BSD, mature, inactive since 2010)
- Infinite Tux (Java, GPL-3.0, Public domain, mature)
- INSTEAD (C, Lua, Java, MIT, mature)
- Intersect (C#, MIT, GPL-2.0, beta)
- Intricacy (Haskell, GPL-3.0, beta)
- ioquake3 (C, GPL-2.0, mature)
- iortcw (C, C++, GPL-3.0, mature)
- Jamp (C++, GPL-3.0, beta, inactive since 2009)
- Javelin (Java, GPL-2.0, mature, inactive since 2016)
- Jazz² Resurrection (C#, JavaScript, GPL-3.0, mature)
- JGame (Java, 3-clause BSD, mature, inactive since 2012)
- JSoko (Java, GPL-3.0, mature)
- Julius (C, C++, AGPL-3.0, mature)
- Jump Don't Die (Java, GPL-3.0, mature)
- KevEdit (C, GPL-2.0, mature)
- kiki the nano bot (C++, Public domain, mature, inactive since 2007)
- KlayGE (C++, GPL-2.0, mature)
- Kobo Deluxe (C++, GPL-2.0, beta, inactive since 2007)
- Krank (Python, Public domain, beta, inactive since 2008)
- LGames (C++, GPL-2.0, mature)
- Librerama (GDScript, GPL-3.0, mature)
- LIKO-12 (Lua, Rust, MIT, mature)
- LimonEngine (C, C++, LGPL-3.0, beta)
- LionEngine (Java, GPL-3.0, mature)
- LITIENGINE (Java, MIT, beta)
- Loon Game (Java, C#, Apache-2.0, beta)
- Love2dCS (C#, C++, MIT, mature)
- Lugaru (C++, GPL-2.0, mature)
- Luola (C, GPL-2.0, mature, inactive since 2005)
- LÖVE (C++, zlib, mature)
- Maelstrom (C, C++, GPL-2.0, mature, inactive since 2002)
- ManaPlus (C++, GPL-3.0, mature)
- Mari0 (Lua, MIT, mature, inactive since 2012)
- Maxit (C++, 3-clause BSD, mature, inactive since 2014)
- Me and My Shadow (C++, GPL-3.0, beta)
- MekWars (Java, GPL-2.0, mature)
- Metaforce (C, C++, MIT, beta)
- MicroWar 2.0 (Python, 3-clause BSD, mature, inactive since 2009)
- Minetest (C, C++, Lua, LGPL-2.1, mature)
- mini2Dx (Java, C#, Apache-2.0, mature)
- Minilens (GDScript, GPL-3.0, mature, inactive since 2018)
- MiniPacman (Ada, GPL-3.0, mature)
- Monsterz (Python, WTFPL, beta, inactive since 2007)
- Mr. Rescue (Lua, zlib, mature, inactive since 2016)
- Netrek (C, Custom, mature, inactive since 2009)
- Neverball (C, C++, GPL-2.0, mature)
- Not Pacman (Lua, WTFPL, mature, inactive since 2013)
- NOVA PINBALL (Lua, GPL-3.0, beta, inactive since 2017)
- NullpoMino (Java, 3-clause BSD, mature)
- Numpty Physics (C++, GPL-3.0, beta, inactive since 2016)
- ONScripter (C++, GPL-2.0, mature, inactive since 2020)
- Oolite (Objective-C, C, JavaScript, GPL-2.0, mature)
- Open Horizon (C++, MIT, beta)
- Open Kick-Off (Java, MIT, beta)
- Open Rodent's Revenge (C++, MIT, beta, inactive since 2018)
- Open RSC (Java, C++, C, Objective-C, AGPL-3.0, mature)
- OpenArena (C, GPL-2.0, mature, inactive since 2012)
- OpenBVE (C#, Public domain, mature)
- OpenDiablo2 (Go, GPL-3.0, mature)
- OpenEnroth (C++, LGPL-3.0, beta)
- OpenHV (C#, Lua, GPL-3.0, beta)
- OpenJazz (C++, GPL-2.0, beta)
- OpenKrush (C#, GPL-3.0, beta)
- OpenLara (C++, C, 2-clause BSD, mature)
- OpenLoco (C++, MIT, mature)
- OpenMortal (C++, Perl, GPL-2.0, beta, inactive since 2006)
- openMSX (C++, GPL-2.0, mature)
- OpenRaider (C, C++, GPL-2.0, beta, inactive since 2015)
- OpenRCT2 (C++, GPL-3.0, mature)
- OpenRW (C, C++, GPL-3.0, beta)
- OpenSAGE (C#, LGPL-3.0, beta)
- OpenSpades (C, C++, AngelScript, GPL-3.0, beta)
- OpenSupaplex (C, GPL-3.0, mature)
- OpenTESArena (C++, MIT, beta)
- OPMon (C++, GDScript, GPL-3.0, beta)
- opsu! (Java, GPL-3.0, mature)
- Oreon Engine (Java, GPL-3.0, mature)
- osu! (C#, MIT, beta)
- ouzel (C, C++, Objective-C, 2-clause BSD, beta)
- Overgod (C, GPL-2.0, mature, inactive since 2005)
- PainTown (C++, Java, Python, 3-clause BSD, mature)
- Passage (C++, Public domain, mature, inactive since 2011)
- Penguin Command (C, GPL-2.0, mature, inactive since 2007)
- Pentagram (C++, GPL-2.0, beta, inactive since 2018)
- Performous (C, C++, GPL-2.0, mature)
- PGU (Python, LGPL-2.1, mature)
- Pillows (Python, GPL-2.0, beta, inactive since 2007)
- Pingus (C++, Scheme, GPL-3.0, mature)
- Pixel Dungeon (Java, GPL-3.0, mature, inactive since 2015)
- Pixel Wheels (Java, GPL-3.0, mature)
- PLIB (C++, LGPL-2.0, mature, inactive since 2012)
- PokerTH (C++, AGPL-3.0, mature, inactive since 2017)
- Powerslave EX (C, C++, GPL-3.0, beta, inactive since 2017)
- Primrose (C++, Public domain, mature, inactive since 2009)
- Privateer - Gemini Gold (C++, GPL-2.0, mature, inactive since 2012)
- Project-Uranium-Godot (GDScript, MIT, beta)
- PsyDoom (C, C++, GPL-3.0, mature)
- Puzzle Moppet (C++, WTFPL, mature)
- Pygame---Alien-Invasion (Python, GPL-3.0, beta, inactive since 2018)
- PyKaraoke (Python, C, LGPL-2.1, beta, inactive since 2011)
- pyscroll (Python, LGPL-3.0, mature, inactive since 2018)
- PySol (Python, GPL-2.0, mature, inactive since 2004)
- PyTMX (Python, LGPL-3.0, mature)
- Q (Python, GPL-3.0, mature, inactive since 2013)
- QuakeSpasm (C, GPL-2.0, mature)
- R.E.L.I.V.E. (C++, MIT, beta)
- Rabbit Escape (Java, GPL-2.0, mature)
- Race Into Space (C, C++, GPL-2.0, mature)
- raylib (C, C++, C#, zlib, mature)
- Recursive Runner (C++, GPL-3.0, beta, inactive since 2017)
- Reliquarium (Ada, GPL-2.0, mature)
- Remnants of the Precursors (Java, CC-BY-NC-ND-4.0, mature)
- Ren'Py (C, Python, Ren'Py, LGPL-2.1, mature)
- ResidualVM (C++, GPL-2.0, beta)
- Ri-li (C++, GPL-3.0, mature, inactive since 2007)
- rlvm (C++, GPL-3.0, mature)
- Rocks'n'Diamonds (C, GPL-2.0, mature)
- Rolisteam (C++, JavaScript, GPL-2.0, mature)
- rpgboss (Scala, JavaScript, AGPL-3.0, beta, inactive since 2017)
- Ruby-warrior (Ruby, MIT, beta, inactive since 2012)
- RufasCube (Ada, GPL-2.0, mature)
- RufasSlider (C++, GPL-2.0, mature)
- RufasSwap (Ada, GPL-3.0, mature)
- Scrabble3D (Pascal, GPL-3.0, mature, inactive since 2015)
- Settlers III remake (Java, MIT, beta)
- sfxr (C++, MIT, mature, inactive since 2012)
- Shattered Pixel Dungeon (Java, GPL-3.0, mature)
- Shockolate (C, GPL-3.0, beta)
- Shotgun Debugger (C++, GPL-2.0, mature, inactive since 2005)
- Simon Tatham's Portable Puzzle Collection (C, MIT, mature)
- Simsu (C++, GPL-3.0, mature)
- SLADE (C++, GPL-2.0, mature)
- Slime Volley (C, GPL-3.0, mature, inactive since 2010)
- Slingshot (Python, GPL-2.0, beta, inactive since 2007)
- Sludge (C, C++, Objective-C, LGPL-2.1, mature)
- Snelps (Ruby, LGPL-2.1, beta, inactive since 2012)
- Solar2D (C++, MIT, mature)
- SolarWolf (Python, LGPL-2.1, mature, inactive since 2004)
- Sonic Robo Blast 2 (C, C++, GPL-2.0, mature)
- SpacePeng! (Java, GPL-3.0, mature, inactive since 2017)
- SpaceTrader for Java (Java, GPL-2.0, mature, inactive since 2010)
- Spice Trade (Java, LGPL-2.1, mature, inactive since 2005)
- SRB2Kart (C, C++, GPL-2.0, mature)
- Stareater (C#, GPL-3.0, beta)
- Stockfish (C++, GPL-3.0, mature)
- Stratagus (C++, GPL-2.0, mature)
- SuperFoulEgg (Objective-C, C, MIT, mature, inactive since 2014)
- SuperStarfighter (GDScript, MIT, beta)
- SuperTux (C++, GPL-3.0, beta)
- SuperTuxKart (C++, C, GPL-3.0, mature)
- SuperTuxParty (GDScript, GPL-3.0, beta)
- System Syzygy (Rust, GPL-3.0, mature, inactive since 2018)
- Taisei Project (C, Python, MIT, mature)
- TankistOnline (Python, GPL-3.0, beta)
- Tanks of Freedom (GDScript, MIT, mature)
- Teeworlds (C, C++, zlib, beta)
- TermFrogger (Ada, GPL-3.0, mature)
- TerminalApps (Ada, GPL-3.0, mature)
- TES3MP (C++, GPL-3.0, beta)
- TetraVex (Swift, GPL-3.0, beta)
- The Battle for Wesnoth (C, C++, Java, Python, Lua, GPL-2.0, mature)
- The Bub's Brothers (Python, C, MIT, mature, inactive since 2013)
- The Butterfly Effect (C++, GPL-2.0, beta)
- The Eternity Engine (C, C++, GPL-3.0, mature)
- The Mana World (C++, Script, GPL-2.0, mature)
- The Powder Toy (C++, C, Lua, Python, GPL-3.0, mature)
- TheXTech (C++, GPL-3.0, mature)
- TIC-80 (C, Java, C++, Lua, MIT, beta)
- TinTin++ (C, GPL-3.0, mature)
- Tiny Wings (Objective-C, C, C++, MIT, beta)
- Torque 2D (C++, C, MIT, mature)
- Torque 3D (C++, C, MIT, mature)
- Total Annihilation 3D (C++, C, Lua, GPL-2.0, beta, inactive since 2017)
- Transcend (C++, ?, beta, inactive since 2005)
- Tremulous (C, GPL-2.0, mature, inactive since 2016)
- Tux Builder (GDScript, GPL-3.0, beta)
- Tux Paint (C, C++, GPL-2.0, beta)
- Tuxemon (Python, GPL-3.0, beta)
- Ultimate Stunts (C++, GPL-2.0, beta, inactive since 2013)
- UltraStar Deluxe (Pascal, GPL-2.0, mature)
- UltraStar Play (C#, MIT, beta)
- Umoria (C, C++, GPL-3.0, mature)
- Unciv (Kotlin, MPL-2.0, mature)
- unitystation (C#, AGPL-3.0, beta)
- Unvanquished (C, C++, GPL-3.0, mature)
- VASSAL (Java, LGPL-2.1, mature)
- VCMI (C++, GPL-2.0, mature)
- VDrift (C++, GPL-3.0, mature, inactive since 2014)
- vkQuake (C, C++, GPL-2.0, mature)
- Wagic, the Homebrew (C++, C, Objective-C, 3-clause BSD, beta)
- Word War vi (C, GPL-2.0, mature)
- X-Moto (C++, GPL-2.0, mature, inactive since 2014)
- XPilot NG (C, GPL-2.0, mature, inactive since 2010)
- XSkat (Java, Custom, mature)
- Yet Another Engine (MoonScript, Java, Lua, MIT, beta, inactive since 2016)
- Yo Frankie! (Blender Script, ?, mature, inactive since 2009)
- YSoccer (Java, GPL-2.0, mature)
- Zandronum (C, Custom, mature, inactive since 2017)
- Zaz (C++, GPL-3.0, beta, inactive since 2010)
- ZDoom (C, C++, ZenScript, GPL-3.0, mature)