Homepage: odamex.net
Inspirations: Doom, Doom II, Heretic, Hexen
Developers: Alex Mayfield, Charlie Gunyon, DeathEgg, Denis Lukianov, drivingspectrum, joffb, John D. Corrado, jsd1982, Maëllig Desmottes, Michael Wood, Mike Lightner, Nick, Ralph Vickers, RestlessRodent, SapientLion, Sean Leonard, Stephen McGranahan, William Breathitt Gray

Homepages: ogrian.sourceforge.net, ogrian
Inspiration: Magic Carpet
Developers: Jeremiah D. Powell, Mike Prosser, Wh-

Homepages: opengamestudio.org/en/game/ogs-mahjong-1.html, osrpgcreation
Inspiration: Mahjong
Download: osrpgcreation/files/Mahjong
Developers: AleXXandEr, Kai SD, kornerr, kornerrjenkins, Opensource Game Studio, xmorph

Homepage: osgg
Download: osgg/files
Developers: Dmitry Marakasov, Jimmy, Jimmy Christensen

Homepage: movitto/omega
Developers: Mo Morsi, Mohammed Morsi, Nicolas Satragno, Nina Satragno

Homepage: davidgow.net/keen/omnispeak.html
Inspiration: Commander Keen Series
Developers: David Gow, Martin Fiedler, NY00123, owenmpierce, Szilárd Biró

Homepages: onehouronelife.com, jasonrohrer/OneLife
Media: One Hour One Life
Developers: Jason Rohrer, Justin Love

Homepages: Archive: 20180724071018/https://hectigo.net/games/oneisenough, packages.debian.org/search?keywords=oneisenough
Developer: Olli Etuaho

Homepage: gordebak.itch.io/onewaytogo
Inspiration: Sensitive

Homepages: lgames.sourceforge.net/OCC, lgames
Download: lgames/files/occ
Developer: Michael Speck

Homepage: onscripter.osdn.jp/onscripter.html
Inspiration: NScripter

Homepages: www.oolite.org, wiki.alioth.net/index.php/Oolite_Main_Page, aegidian.org/bb/index.php
Media: Oolite
Inspiration: Elite
Download: oolite.org/download
Developers: AnotherCommander, cim, DaymareOn, Eric Walch, Jens Ayton, jobi-wan, Kaks, Kevin Anthoney, Konstantinos Sykas, Nick Rogers, phkb

Homepage: openapoc.org
Inspirations: X-COM: Apocalypse, X-COM: Terror from the Deep, X-COM: UFO Defense
Download: ci.appveyor.com/project/openapoc/openapoc
Developers: 5thAvenue, Alexey Rogachevskiy, Code., Daniel, emptyVoid, FilmBoy84, Francisco Altoe, Istrebitel, Ivan Shibanov, Jacob Deuchar, Jari, Jonathan Hamilton, Kirill Mishustin, makus82, Marq Watkin, Pavel Antokolsky, redv, ShadowDancer, SiemensSchuckert, Silviu Ghita, sparkstar, Steve Schnepp, Vasiliy Panasenko, Xracer

Homepage: team-cube.github.io
Inspiration: Cube 2: Sauerbraten
Developer: Henry Hirsch

Homepage: GunshipPenguin/open_flood
Downloads: play.google.com/store/apps/details?id=com.gunshippenguin.openflood, f-droid.org/packages/com.gunshippenguin.openflood
Developer: Rhys Rustad-Elliott

Homepage: openfodder.com
Inspiration: Cannon Fodder
Developers: drnovice, Robert Crossfield

Homepage: openfortress.fun
Inspiration: Team Fortress 2

Homepage: troel.net/opengreedy
Inspiration: Pac-Man
Developer: atroel

Homepage: vittorioromeo.info/projects.html
Inspiration: Super Hexagon
Developers: AlphaPromethium, byte-chan™, IvoryDuke, kiwec, Matija Skala, Mischa Alff, Synth Morxemplum, treier57lol, Vittorio Romeo, Wolf Clément, Zly

Homepage: zxstudio.org/blog/author/razgriz
Inspiration: Ace Combat: Assault Horizon
Download: zxstudio.org/blog/open-horizon-downloads
Developer: undefined-darkness

Homepage: open-ig-dev.blogspot.com
Inspiration: Imperium Galactica
Download: akarnokd/open-ig/releases
Developers: David Karnok, Péter Kovács, Robikz

Homepages: opengate.sourceforge.net, opengate
Inspiration: Jumpgate: The Reconstruction Initiative
Developers: Christoph Brill, Daniel S., spom_spom

Homepage: ssenegas/kickoff
Inspiration: Kick Off 2
Download: ssenegas/kickoff/releases

Homepage: openlegendrpg.com
Developers: Brian Feister, Cryogenic, Fabio Endrizzi, istabosz, Mario Lurig, Matthew O'Connor, Michael Loubier, R.J. Wood

Homepage: openmeridian.org
Inspiration: Meridian 59
Download: openmeridian.org/create-account
Developers: Andrew Chrapko, Ashton, broodhill, Clint Banzhaf, Daenks, FSU-Phil, M59Gar, M59Khan, Mark Sturm, Matthew Trey, Meridian59, Morbus, PKChrisChan, Roy, Sarevok, siwithaneye, skittles1, theanax, tsShergill, xFirekatx

Homepage: www.linuxconsulting.ro/openpanzer
Inspiration: Panzer General 2
Developers: Iulian Luca, Nicu Pavel

Homepages: openquartz.sourceforge.net/index.html, openquartz
Download: openquartz/files
Developers: Bill Currie, Charles Galbraith, David Costanzo, Gargoylol, Mapes, Seth Galbraith, Toddd

Homepage: openrails.org
Inspiration: Microsoft Train Simulator
Download: openrails.org/download/program

Homepages: pierreyoda/o2r, o2r
Inspiration: Rodent's Revenge
Downloads: pierreyoda/o2r/releases, o2r/files
Developers: Pierre, Pierre-Yves

Homepages: rsc.vet, runescapeclassic.dev, Archive: 20200510133848/https://openrsc.com
Inspiration: Runescape Classic
Developers: Aenge, aldrichdev, Bl0ds, Brian Foster, Chris, Daniel Loth, Fefect, Hubcapp, ipkpjersi, James Wallen-Jones, Kenix3, Kepler, kevincmanning, Luis Salazar, Marwolf, Payton, Preston Smith, rsc-g15, Ryan Trujillo, Tessalicious, xjoe28, Zachariah Knight

Homepage: opensimulator.org/wiki/Main_Page
Inspiration: Second Life
Download: opensimulator.org/wiki/Download

Homepage: opensoccerstar.com
Developer: Daniel Mecke

Homepages: opensurge2d.org, opensnc.sourceforge.net/home/index.php, opensnc.sourceforge.net/forum/index.php, opensnc
Inspiration: Sonic the Hedgehog series
Downloads: opensnc.sourceforge.net/forum/viewtopic.php?id=1931, opensnc.sourceforge.net/home/download.php
Developers: Alexandre Almeida, Alexandre Martins, Arthur Blot, Christian Zigotzky, Christopher Martinus, Francesco, Halatnikov, Reimund Renner, SecularSteve, Stylix58, Szymon Weihs, Tomires

Homepage: opensyobon
Inspiration: Shobon Action
Download: opensyobon/files
Developer: Mathew Velasquez

Homepages: opentibia, opentibia
Inspiration: Tibia
Download: opentibia/files
Developers: 13r, adakraz, Alexandre Severino, Anstice, Arkold Thos, Artur Pacan, assassina, Assassina Mutante, Axel, Daniel Antunes, Dennis, Eduardo Bart, Elf, fike, Gilfar, GriZzm0, Haktivex, Hampus Joakim Borgos, Hampus Joakim Nilsson, Heliton, Ivan Vučica, jakexblaster (Marcos Cunha), Jiddo, johannesrosenqvist, johnny8020, Konrad Kuśnierz, Luis Hernandez, Mark Samman, mips, Nate Fries, OsoSangre, pedro_b, Piotr Walaszczyk, Rafael Hamdan, Rafał Wrzeszcz, Remere, René Mujica Moreau, Ricochet, Roberto, Simone, smyg, Sorcuring, Stefan Maier, Sven Matner, Thomaz Yuji, Thomaz Yuji Babá, Vitor, Winghawk

Homepage: mastodon.gamedev.place/@OpenValley
Inspiration: Stardew Valley

Homepages: www.openyahtzee.org, openyahtzee
Inspiration: Yahtzee
Downloads: www.openyahtzee.org/wiki/download, openyahtzee/files
Developers: Guy Rutenberg, Journeyman, smcgill

Homepages: openzelda/openzelda-source, Archive: 20171028213428/http://openzelda.nfshost.com
Inspiration: Legend of Zelda

Homepage: openage.sft.mx
Inspirations: Age of Empires, Age of Empires II, Star Wars: Galactic Battlegrounds
Developers: Akritas Akritidis, Alex Antonov, Andrew Eikum, Andrew Thompson, azrdev, Birch-san, Charles Pigott, Christoph Heine, D R Siddhartha, Danilo Bargen, Darren Strash, Francisco Demartino, Frank Schmidt, Jasper v. B., jgelderloos, Jimmy Berry, Johan Klokkhammer Helsing, Johannes Walcher, Jonas Jelten, Jonathan, Kevin Peters, Lorenzo Gaifas, Markus Otto, masi456, Mayeul Cantan, Michael Enßlin, Michael Sebastiyan, Michał Janiszewski, Miguellissimo, Niklas Fiekas, Piruzzolo, Prashanth Jonnala, PythonicChemist, Qingnan Duan, Renée Kooi, Samuel Schetterer, Sascha Vincent Kurowski, Sebastian Brodehl, Serhan Tutar, simonsan, spjoe, Tobias Feldballe Petersen, Tushar Maheshwari, Velkan, Wilco Kusee, Wojciech Nawrocki, Yvan Burrie

Homepages: www.openalchemist.com, openalchemist
Inspiration: NaturalChimie
Downloads: www.openalchemist.com/downloads.php, openalchemist/files
Developers: Antoine Morineau, Gecko667, guigoz, Guillaume Delhumeau, MrPouit, silkut

Homepage: openarena.ws/smfnews.php
Media: OpenArena
Inspiration: Quake III Arena
Download: openarena.ws/download.php
Developers: Anthony Pesch, Ensiform, hairball, Jack Slater, James Canete, Jeremiah Sypult, leilei-, Ludwig Nussel, Poul Sander, Richard Allen, Ryan C. Gordon, Sui Jingfeng, Thilo Schulz, Tim Angus, Tony White, Zack Middleton

Homepages: openblack/openblack, forum.bwgame.net
Inspiration: Black & White
Developers: Matt Stevens, Michał Janiszewski, NeroBurner, raffclar, Sandy

Homepage: mmatyas/openblok
Inspiration: Tetris
Download: mmatyas/openblok/releases
Developer: Mátyás Mustoha

Homepages: Archive: 20121114113914/http://openblox.sourceforge.net, openblox
Download: openblox/files
Developers: Alfredzo Nash, Bednesti, brutustodd, Chris Bradley, DangerOnTheRanger, Danny Green, Oliver Frye, TheEnd

Homepage: www.chronocrash.com/forum
Inspirations: Double Dragon, Final Fight, Streets of Rage
Developers: Bryan Cain, Carlos Donizete Froes, CRxTRDude, Damon V. Caskey, Jan Beich, Kratus, Malik, SumolX, utunnels, Wasin Thonkaew, White Dragon

Homepage: openbve-project.net
Inspiration: BVE Trainsim
Download: openbve-project.net/download
Developers: Christopher Lees, Connor Fitzgerald, Jakub Vaněk, Marc Riera, Maurizio M. Gavioli, s520

Homepage: Archive: 20110223210931/http://openc2e.org
Media: creatures.fandom.com/wiki/Openc2e
Inspiration: Creatures
Developers: Alyssa Milburn, bdonlan, Eric Goodwin, Jeremy Rose, ligfx

Homepages: www.opencity.info, opencity
Media: OpenCity
Inspiration: SimCity
Download: www.opencity.info/en/Download.html
Developers: Duong Khang NGUYEN, frodrigo

Homepage: pjasicek/OpenClaw
Inspiration: Claw
Developers: Bakasura, Denis Papec, Dmitrii Dementev, Pavel Löbl, Petr Jašíček

Homepage: www.openclonk.org
Media: OpenClonk
Inspiration: Clonk
Download: www.openclonk.org/download
Developers: Armin, Armin Burgmeier, Armin Scheurens, Benjamin Herr, boni, ckanibal, David Dormagen, Ewan Mellor, Fabian Pietsch, Felix Wagner, Fulgen301, gitMarky, isilkor, jcaesar, Kevin Zheng, Linus Heckemann, Lukas Werling, Maikel de Vries, Meowtimer, Peter Wortmann, Philipp Kern, Sven, Tobias Zwick, Tushar Maheshwari, Urschel

Homepage: gurka/OpenCrystalCaves
Inspiration: Crystal Caves
Developer: Simon Sandström

Homepage: opendiablo2.com
Inspiration: Diablo 2

Homepage: www.opendominion.net
Inspiration: Dominion
Developers: barmmie, Christopher Smith, Cody Kinsey, Guilherme Portela, Gustavo Straube, Jake, James Hodgson, John Strömblom, Kender2, MJBrennan, WaveHack

Homepage: rofl0r/openDOW
Inspiration: Dogs of War
Developer: rofl0r

Homepage: OpenDUNE/OpenDUNE
Inspiration: Dune 2
Download: OpenDUNE/OpenDUNE/releases
Developers: drnovice, glx22, KO Myung-Hun, Loïc Guilloux, Máximo Castañeda, Olaf van der Spek, Patric Stout, Thomas BERNARD, wangds, Xaroth

Homepage: opendungeons.github.io
Inspiration: Dungeon Keeper
Download: opendungeons.github.io/downloads.html
Developers: 4562448, Bebere, BorQube, Danimal696, David CARLIER, hwoarangmy, Ian T. Jacobsen, oyvindln, Pavel Rojtberg, Rémi Verschelde, tomluchowski, Yohann Ferreira

Homepage: etg.dek.im
Inspiration: Elements
Play online: etg.dek.im
Developers: Philip Dubé, Trevor Sayre, Wesley M. Botello-Smith

Homepage: Last-Minute-Creations/openFire
Inspiration: Fire Power
Developer: KaiN

Homepage: ariel.ucs.unimelb.edu.au/~gjo
Inspiration: Flight Sim Toolkit

Homepage: MotoLegacy/OpenFNaF
Inspiration: Five Nights at Freddy's
Developers: darkhaven3, Ian

Homepage: Archive: 20190801083807/http://sourceforge.net/projects/openggs
Inspiration: The Great Giana Sisters
Download: Archive: 20190515074042/https://sourceforge.net/projects/openggs/files

Homepage: antongerdelan.net/blog/formatted/2014_12_10_test_drive.html
Inspiration: Test Drive
Developer: Anton Gerdelan

Homepages: snowstorm.sourceforge.net/cgi-bin/site.cgi?page=home, snowstorm
Inspiration: Gladiator
Download: snowstorm.sourceforge.net/cgi-bin/site.cgi?page=download
Developers: Jonny D, Sean Ford, Zardus

Homepage: Try/OpenGothic
Inspirations: Gothic, Gothic II
Download: Try/OpenGothic/releases
Developers: ErrorFlexXx, Try, Álvaro "da3m0n"

Homepages: launchpad.net/openhomm, heroes-rebirth
Inspiration: Heroes of Might and Magic III
Download: launchpad.net/openhomm/+download
Developers: crackedmind, Ice

Homepage: TalonBraveInfo/OpenHoW
Inspiration: Hogs of War
Developers: Bonerlord, Daniel Collins, DummkopfOfHachtenduden, Mark Sowden, Stefano

Homepage: openhv.itch.io/openhv
Media: www.gamingonlinux.com/2020/09/a-cancelled-old-rts-named-hard-vacuum-gets-revived-with-openra
Inspirations: Command & Conquer, Dune 2, KKND, StarCraft
Download: OpenHV/OpenHV/releases
Developers: Dzierzan, Matthias Mailänder, Paweł Dzierżanowski, Zimmermann Gyula

Homepages: openitg.gr-p.com, openitg/openitg/wiki
Inspiration: StepMania
Developers: August Gustavsson, Carl Myers, DataBeaver, Kate Gray, mooinglemur, spigwitmer, Toni Spets, vyhd

Homepage: www.alister.eu/jazz/oj
Inspiration: Jazz Jackrabbit
Download: www.alister.eu/jazz/oj/download.php
Developers: AlisterT, Carsten Teibes, Fabian Greffrath, Mike Purvis, Przemysław Buczkowski, Scott, StanB123

Homepage: JACoders/OpenJK
Inspirations: Star Wars Jedi Knight II: Jedi Outcast, Star Wars Jedi Knight: Jedi Academy
Download: builds.openjk.org
Developers: Alex Lo, Alex Nordlund, Alexandre Blin, Anonymous Maarten, Archangel35757, Boris I. Bendovsky, Brandon Largeau, Dion Williams, Ensiform, Harry Jeffery, Joel Teichroeb, Lourens Elzinga, Nathaniel Brandes, Nick, ouned, razor, redsaurus, Scooper, Simon McVittie, Szilárd Biró, Taahir Ahmed, Willi Schinmeyer, Zack Middleton

Homepage: tonihele/OpenKeeper
Inspiration: Dungeon Keeper 2
Developers: ArchDemons, belgianguy, Petteri Loisko, Toni Helenius, ufdada

Homepage: www.kknd-game.com/index.php
Media: OpenKrush
Inspiration: Krush Kill 'n' Destroy
Developers: abcdefg30, Andre Mohren, Dzierzan, Paul Chote, taryn

Homepage: XProger/OpenLara
Inspiration: Tomb Raider
Play online: xproger.info/projects/OpenLara
Developers: Gh0stBlade, laripette, Leo-89, Manuel Alfayate Corchete, Pablo Maiolo, SaracenOne, Timur Gagiev, Torsten Kammer, vaguerant, vanfanel2

Homepages: www.liero.be, code.google.com/archive/p/liero
Inspiration: Liero
Developers: Anders Höckersten, gliptic

Homepage: www.openlierox.net
Inspirations: Liero, Worms
Downloads: www.openlierox.net/downloads, openlierox/files
Developers: Albert Zeyer, Karel Petránek, lxkurko, Martin Erik Werner, Olof Larsson, Sergii Pylypenko, yuri

Homepage: OpenLoco/OpenLoco
Inspiration: Chris Sawyer's Locomotion
Download: OpenLoco/OpenLoco/releases
Developers: Aaron van Geffen, ceeac, Duncan, Justin Gottula, Kane, Marijn van der Werf, Michael Steenbeek, Michał Janiszewski, Peter Gaal, Richard Jenkins, Svelbeard, Ted John, TELK, Zcooger, ζeh Matt

Homepage: LRFLEW/OpenMC2
Inspiration: Midnight Club II
Developers: Duncan, LRFLEW

Homepage: Jakz/openmom
Inspiration: Master of Magic
Developer: Jacopo Santoni

Homepages: pjotrligthart/openmoo2-hg-mirror, Archive: 20191221224844/http://openmoo2.org/en
Inspiration: Master of Orion 2
Download: Archive: 20191229125931/http://openmoo2.org/en/download
Developer: II9T5

Homepages: apocalypse.rulez.org/~upi/Mortal, openmortal
Inspiration: Mortal Kombat
Download: openmortal.sourceforge.net/download.html
Developers: arvind, Gabor Sebestyen, Kami, openmortaldev, UPi

Homepages: openmsx.org, openmsx
Downloads: openMSX/openMSX/releases, openmsx/files
Developers: Albert Beevendorp, Alex Wulms, Arnold Metselaar, boukichi, D15C0DE, David Heremans, Edwin, Eric Boon, Filip H.F. "FiXato" Slagter, Herman Oudejans, Joost Yervante Damad, Laurens Holst, Maarten ter Huurne, Manuel Bilderbeek, Max Feingold, Patrick van Arkel, peterhanraets, Reikan, Sandy Pleyte, sdsnatcher73, Sean Young, Wouter Vermaelen

Homepage: openmw.org/en
Media: OpenMW
Inspiration: The Elder Scrolls III: Morrowind
Download: openmw.org/downloads
Developers: Alex, Alexander "Ananace" Olofsson, Alexander Nadeau, Alexander Stillich, Alexandre Moine, Alexei Dobrohotov, Allofich, Andrei Kortunov, Anton Uramer, arbitrary-dev, Artem Kotsynyak, Artem Utin, Arthur Moore, Assumeru, astillich-igniti, athile, Aussiemon, Austin Salgat, Azdul, Bo Svensson, Bodillium, Bret Curtis, Britt Mathis, cc9cii, cfcohen, Chris Djali, Cody Glassman, Cramal, Cédric Mocquillon, darkf, David Cernat, David Walley, Dmitry Marakasov, dteviot, Edmondo Tommasina, endorph, eroen, Fil Krynicki, Finbar Crago, fr3dz10, Gleb Mazovetskiy, Gohan1989, gugus, halalstuff, Hristos N. Triantafillou, Internecine, Jackerty, Jacob Essex, James Carty, Jan Borsodi, Jan-Peter Nilsson, Jason Hooks, Jeffrey Haines, Jiří Kuneš, Joakim Berg, Joel Graff, Jordan Ayers, Jordan Milne, Josua Grawitter, jrivany, Julien Voisin, k1ll, Kamil Bar, kcat, Kevin, Kyle Cooley, Lennart Bernhardt, logzero, Lukasz Gromanowski, M S, Madcow, Mads Sandvei, Marc Zinnschlag, Marco Melletti, marcrbouvier, Marek Dudek, Marek Kochanowicz, Mark76, MAtahualpa, MatthewRock, Max Henzerling, Michael Mc Donnell, Michael Papageorgiou, Michał Bień, Miloslav Číž #movingToGitLab, Miroslav Puda, MiroslavR, Mitchell Schwitzer, MocquillonCedric, Nathan Aclander, Nathan Jeffords, Nicolay Korslund, Nikolay Kasyanov, Oleg, Perry Hugh, Phillip Andrews, pi03k, Pieter van der Kloet, PL_kolek, PlutonicOverkill, Rafael Moura, rainChu, rexelion, rhtucker, riothamus, Rob Cutmore, Robert MacGregor, Rohit Nirmal, Roman, Roman Melnik, Roman Proskuryakov, Roman Siromakha, sandstranger, Sandy, Scott Howard, Sebastian Wick, Sergey Fukanchik, Sergey Shambir, sergoz, Simon Humpohl, slothlife, Sophie Kirschner, Stanislav Bas, Stanislaw Halik, Starsickle, Sylvain T, Tatrabbit, terrabyte25, Thoronador, Thunderforge, Tom, Tom Mason, TorbenC, tri4ng1e, unelsson, Xenkhan, xyzz, Yuri Krupenin, zelurker, Łukasz Gołębiewski, ⴹⅿаոuel GuéveΙ

Homepage: omw.xyz.is
Inspiration: The Elder Scrolls III: Morrowind
Downloads: play.google.com/store/apps/details?id=is.xyz.omw, f-droid.org/packages/is.xyz.omw
Developers: Bret Curtis, Licaon_Kter, sandstranger, xyzz

Homepage: opennfs.com
Inspiration: Need For Speed III: Hot Pursuit
Developer: Amrik Sadhra

Homepage: verhoevenv/OpenNotrium
Inspiration: Notrium
Developers: Eduardo Pinho, Vincent Verhoeven

Homepage: www.openomf.org
Media: OpenOMF
Inspiration: One Must Fall: 2097
Downloads: www.openomf.org/downloads, omf2097/openomf/releases
Developers: Alexander Weps, Andreas Gnau, Andrew Thompson, animehunter, Giuseppe Deda, Martti Rannanjärvi, TheOnlyJoey, Tuomas Virtanen

Homepage: www.openra.net
Media: OpenRA
Inspirations: Command & Conquer, Command & Conquer: Red Alert, Dune 2000
Download: www.openra.net/download
Developers: abc013, abcdefg30, abmyii, Adam Mitchell, Alexander Fast, alexander-boll, Alexandre Oliveira, Alexis Hunt, Alfredo Brandau, Alli, Andre Mohren, Andrew Odintsov, anvilvapre, AoAGeneral, Arular101, atimoschenkow, atlimit8, BGluth, blackhand1001, Booom3, Braxton Williams, Carko, CH4Code, Chris Forbes, Christopher Grant, clemty, Clément Bœsch, Cody Brittain, Curtis Shmyr, Daniel Hernandez, Danny Keary, darkademic, David Jiménez, David Wilson, DeadlySurprise, Deniz, Dmitri Suvorov, dnqbob, DSUK, earthpig, epicelite, evgeniysergeev, forcecore, fruestueck, Glenn Martin Jensen, GSonderling, Gustas, Heli Aldridge, Hellhake, HenrytheSlav, Ian T. Jacobsen, Igor Popov, Inq8, Ivaylo Draganov, Jacob Dufault, Jan Beich, John Turner, Jonas A. Lind, Jonathan Ling, jrb0001, jsd1982, Kanar, Kenny Hoxworth, Kevin, Kyrylo Silin, ltem, Markus Hartung, Matija Hustić, Matthias Mailänder, MatthijsBenschop, Max Ugrumov, Micr0Bit, MorMund, Moviuro, Mustafa Alperen Seki, mvdhout1992, Nah, Neth, Nikolay Fomin, Oliver Brakmann, OmegaBolt, Orb370, Paolo Chiodi, Paul Chote, Paul van Tilburg, Pavel Penev, Pavlos Touboulidis, Peter Antal, Peter Evers, Pi Delport, psydev, r0b0v, Raymond Bedrossian, raz, reaperrr, Remco, Robert Rouhani, RoosterDragon, s1w_, Sam, Scott, sinf, Smittytron, SteelPhase, taryn, teees, teinarss, TheChosenEvilOne, Thijs Waalen, Tim M, tovl, Trevor Nichols, Tyson Liddell, UberWaffe, Unrud, Wojciech Walaszek, xan2622, yesfish, ytinasni, Zimmermann Gyula

Homepages: xythobuz/OpenRaider, openraider.sourceforge.net, openraider
Inspiration: Tomb Raider
Download: xythobuz/OpenRaider/releases
Developers: Carsten Teibes, Terry 'Mongoose' Hendrix II, Thomas Buck

Homepages: openrct2.io, openrct2.org
Media: OpenRCT2
Inspirations: RollerCoaster Tycoon, RollerCoaster Tycoon 2
Download: openrct2.org/downloads
Developers: A.N, Aaron van Geffen, Adam, Adrian Wielgosik, Albert Morgese, Alexander Overvoorde, Andy Ford, annoyingdroid, anyc, atmaxinger, aw20368, Basssiiie, Ben Johnston, Ben Pye, blackhand1001, Breno Rodrigues Guimarães, Bryan DiLaura, camthesaxman, ceeac, Chanwoong Kim, Cheetos420, Christian F. Coors, Christian Murphy, Christian Schubert, Cody Jung, Cory Sanin, CraigCraig, Daan de Heij, danidoedel, Daniel Kamil Kozar, Daniel Karandikar, Daniel Trujillo Viedma, Daniël Heres, Dennis Devriendt, Dennis-Z, deurklink, Dom Light, Duncan, DutchRPW, Dániel Tar, frutiemax, Gabriel Guedes, Gericom, GingerAdonis, Graham Edgecombe, Harry Lam, Haven Kim, Helio Nunes Santos, Hendrik v. Raven, hexdec, Hielke Morsink, hokasha2016, Hudson Oliveira, irrelevantirreverent, Jackson Davis, James, jensj12, Jeroen Sack, JeroenDStout, Jim, Jim Armstrong, Jonathan Haas, Joshua Moerman, Josue Acevedo, Julia Pinheiro, Justin Gottula, Jørn Lomax, Kane, Keatzee, Keith Stellyes, Kevin, Kevin Burke, Krutonium, Kyle Kirbatski, Leurak, Linus Unnebäck, LRFLEW, Lucas Åström, Maciek Baron, Maikel Stuivenberg, MaikelS11, Manuel Vögele, Marco Costa, marcovmun, Margen67, Marijn van der Werf, Martin Černáč, Mathias Gibbens, Matt Souza, Matte A, Matthias Lanzinger, Matthias Mailänder, Melissa, Michael Steenbeek, Michał Janiszewski, Michiel, Miso Zmiric, muemart, Mustapha Elghoul, NathanIkola, nexgenration, Nicolas Hawrysh, nightroan, Nils Caspar, Olivier Wervers, OpenRCT2 git bot, oystedal, Patrick Wijnings, Paul Sajna, Paweł Bylica, Peter, Peter Hill, Peter Ryszkiewicz, Philip Goto, Phillip Walters, pizza2004, pkubaj, platipo, Pulkit, quale, Richard Fine, Richard Jenkins, Richard Qian, Robert Jordan, Rodbourn, RollingStar, rpstester, Ruben De Smet, Rune Laenen, Saad Rehman, Sadret, Sam Horn, Sidney, Sijmen, Silent, Simon J, skdltmxn, Skip, spacek531, Ted John, TELK, TheAssassin, Thomas den Hollander, Timmy Weerwag, Tobias Kohlbau, Tom Lankhorst, Tom Parsons, Tom van der Kleij, Tomas Dittmann, TomasZilinek, Trevor Harkness, Trevor Wilson, Tulio Leao, Umdlye, Vinicius Sa, w-flo, William Wallace, wolfreak99, X123M3-256, Xkeeper, xperia64, Yannic Geurts, Yaroslav Tretyakov, YJSoft, zaxcav, Łukasz Pękalski, ζeh Matt

Homepage: openroadsgame.com
Inspiration: SkyRoads
Play online: openroadsgame.com
Developer: Daniel Church

Homepages: Archive: 20150412083852/https://www.pygame.org/projects/22/189, Archive: 20070305102426/http://arrakis.sourceforge.net/wiki/index.php?OpenRTS, arrakis
Download: arrakis/files
Developers: Andreas Røsdal, Rtsfan

Homepage: openrw.org
Inspiration: Grand Theft Auto III
Developers: aldoxtor, Anonymous Maarten, Christoph Heiss, Daniel Evans, darkf, haphzd, Jannik Vogel, Leo Moser, Lucas, Marco Schmidt, mole99, NFSMONSTR, Paul Kocialkowski, qkolj, shfil, Sven Stucki, tsjost

Homepage: www.moddb.com/mods/opensa
Inspiration: Swarm Assault
Developers: abcdefg30, Dzierzan, Matthias Mailänder, Paul Chote, taryn, Zimmermann Gyula

Homepages: opensage.github.io, timjones.io/blog/tags/opensage
Inspiration: Command & Conquer: Generals
Download: OpenSAGE/OpenSAGE/releases
Developers: Birgit, Daan Meijer, Daniel Sklenitzka, hashkitten, Jana Mohn, Lanyi, Markus Hiller, Michael Schnabel, Paavo Huhtala, Stephan Vedder, Tim Jones, Tyler Reynolds, Voldie

Homepage: nicholas-ochoa/OpenSC2K
Inspiration: SimCity 2000
Developer: Nicholas Ochoa

Homepage: openskyscraper.org
Inspiration: SimTower
Developers: Fabian Schuiki, Hoshi, matthewharvey

Homepage: delight-im/OpenSoccer
Developers: cosme12, Diego Lanciotti, Marco

Homepage: mdodis/OpenSolomonsKey
Inspiration: Solomon's Key
Developers: immortalx74, Michael Dodis

Homepages: openspades.yvt.jp, sites.google.com/a/yvt.jp/openspades
Inspiration: Ace of Spades
Download: yvt/openspades/releases
Developers: ArionWT, Chameleonhider, Damien Flament, David CARLIER, Dennis Barzakovsky, Dmitry Marakasov, Flávio Monteiro, Hanju Yoo, Ilia, Ilia Sidorenko, John Ericson, João Rodrigues, Kent Delante, Marco Schlumpp, Masaki Yamahata, Nick Renieris, NotAFile, Pablo Dallegri, teodor6140, yvt

Homepage: ObKo/OpenSR
Inspiration: Space Rangers 2: Dominators
Developers: Alexander Akulich, Dmitrii Kosarev, Kakadu, Konstantin Oblaukhov

Homepage: sergiou87/open-supaplex
Inspiration: Supaplex
Developers: Alexey Sokolov, Cameron Cawley, Cillié Malan, mills32, Román Jiménez, Sergio Padrino

Homepage: openswe1r.github.io
Inspiration: Star Wars Episode I: Racer
Developers: Jannik Vogel, Tobias Taschner

Homepage: afritz1/OpenTESArena
Inspiration: The Elder Scrolls: Arena
Developers: Aaron, Allofich, Dozayon, kcat, Malcolm Mallardi, MinganMuon, Robert MacGregor, Thunderforge

Homepages: opentitus.sourceforge.net, opentitus, opentitus.fandom.com/wiki/OpenTitus_Wiki
Inspiration: Titus the Fox
Download: opentitus/files/opentitus
Developers: Eirik Stople, stople

Homepage: opentomb.github.io
Inspiration: Tomb Raider
Download: opentomb/OpenTomb/releases
Developers: Adrien RICCIARDI, Federico Barlotti, Filipe Freire, Gabriel Mtz, Gh0stBlade, Sai-sai, Steffen Ohrendorf, TeslaRus, Timur Gagiev, TokyoSU, Tom Niget, Tom Pritchard, Torsten Kammer, vvs-

Homepage: benjaminfoo/OpenTriad
Inspiration: Triple Triad
Developer: Benjamin Fuu

Homepage: www.openttd.org
Media: OpenTTD
Inspiration: Transport Tycoon
Download: www.openttd.org/downloads/openttd-releases/latest.html
Developers: Alberth289346, Alexander Weiss, Andy, Bernard Teo, Brendon Green, Charles Pigott, Dan Villiom Podlaski Christiansen, Didac Perez Parera, dP, Eddi-z, embeddedt, Emil Djupfeldt, frosch, Gabda, glx22, Greg-21, Henry, Ingo von Borstel, JMcKiern, Joan Josep, Joe Stringer, Jonathan G Rennison, Juriy Petrochenkov, Loïc Guilloux, Matt Kimber, Matthijs Kooijman, Michael Lutz, Milek7, Niels Martin Hansen, nikolas, Owen Rudge, Patric Stout, Pavel Stupnikov, PeterN, rubidium42, SamuXarick, sean, stormcone, TELK, Thijs Marinussen, Tyler Trahan, Ulf Hermann, Vít Šefl

Homepages: opentyrian/opentyrian, Archive: 20200418041638/https://bitbucket.org/opentyrian/opentyrian/wiki/Home
Inspiration: Tyrian
Developers: Carl Reinke, schmerm, Yuri Kunde Schlesner

Homepage: makipl.github.io/OpenVIII-monogame
Inspiration: Final Fantasy VIII
Developers: Albeoris, Benjamin Fuu, Marcin Gomulak, Robert Russell

Homepage: ihofmann/open-websoccer
Download: ihofmann/open-websoccer/releases
Developer: Ingo Hofmann

Homepage: openxcom.org
Media: OpenXcom
Inspirations: X-COM: Apocalypse, X-COM: Terror from the Deep, X-COM: UFO Defense
Download: openxcom.org/downloads-milestones
Developers: 54x, Alexander Kashev, Alexey Rogachevskiy, alienfood, Andrew Schultz, Andriy B. Kmit', Andriy Kmit', Andrzej Owsiejczuk, Angelos Tzotsos, atlimit8, Azamat H. Hackimov, boozedog, cfailde, cornels, d2uriel, Daniel, DarkDefender, Dmitry Marakasov, dtrushn, Eino Keskitalo, FalkoOXC, Fenyő, Gix, greg, Greg Bonik, Greg V., Guido Pinkas, hackbunny, IvanDogovich, Jaco, Jason Gilbert, Jay Atkinson, JDarthenay, Jonathan Hamilton, kevL, Kim Nilsson, Konstantinos Arvanitis, Krzysztof Knapik, Marq Watkin, Meridian, Myk, NHOrus, Nik Konyuchenko, nilekurt, OmniscientQ, Player701, R1dO, radius75, redv, Ross Horsman, Ryan C. Creasey, ShadowGJ, sheepo99, Shugyousha, stefkosdev, stiiin, tomvd, Tomáš Chvátal, uqs, Volutar, Warboy1982, Westin Breger, WorMzy Tykashi, Yankes, ZehCastro

Homepage: discord.gg/sjRMQwv
Inspiration: S.T.A.L.K.E.R: Call of Pripyat
Developers: 007exe, a1batross, abramcumner, Alexander Akulich, Alundaio, Andrew Boyarshin, Andrew Davies, Andrey Voitishin, Anton Tsukanov, CasualDev242, David CARLIER, Dmitry Tsarevich, drug007, ensign Curvedhand, FreeZoneMods, George Ivlev, gunslingermod, Igor Novikov, jazzvaz, Jules Blok, Lev Khoroshansky, Max Goncharenko, Mike Nordell, Mikhail Bogdanov, mrnotbadguy, NeoAnomaly, Plotja, q4a, qweasdd136963, r-a-sattarov, RainbowZerg, Robin, Roman Zavalov, ShokerStlk, SkyLoaderr, vamit611, Viktor Stavitsky, vincent-t, vTurbine, Xottab_DUTY, Zegeri

Homepage: Evilpersonwithnosoul/OpenYandere
Inspiration: Yandere Simulator
Developer: HardlyACoolPerson

Homepages: kursk.sourceforge.net, kursk
Download: kursk/files
Developer: Kalman Andrasi

Homepage: opmon-game.ga
Inspiration: Pokémon
Developers: Aerzia, Bobor-dev, Cyrielle, Ethan_Charrier, Jonny Paton, Kévin Bernard-Allies, Michael Vetter, Navet56, Olivier Grech

Homepage: www.zneaker.com/projects.html#orbit
Inspiration: SkyRoads

Homepage: bni.github.io/orbium
Inspiration: Log!cal
Developer: Björn Nilsson

Homepage: fynnfluegge/oreon-engine
Download: fynnfluegge/oreon-engine/releases
Developers: Adrian Romanelli, Fynn Flügge

Homepages: Archive: 20131114051805/http://www.e-circus.org, orient-ecircus
Download: orient-ecircus/files
Developer: Michael Kriegel

Homepage: stephank.github.io/orona
Inspiration: Bolo
Play online: stephank.github.io/orona/bolo.html
Developer: Stéphan Kochen

Homepage: identicalsoftware.com/ostrichriders
Inspiration: Joust
Developers: dulsi, Rémi Verschelde

Homepage: osu.ppy.sh/home
Inspirations: Beatmania IIDX, Osu! Tatakae! Ouendan, Taiko no Tatsujin
Downloads: osu.ppy.sh/home/download, ppy/osu/releases
Developers: Adonais Romero González, Aergwyn, aitani9, Akash Mozumdar, Albert Tang, Albie, Alchyr, Alex Amadori, AlFas, alula, Andrei Zavatski, andy, anellie, Angela Zhang, apollo, BananeVolante, Bartłomiej Dach, Berkan Diler, BlauFx, Charlie, Christian Kamphausen, Christine Chen, ckie, clayton, Craftplacer, Damnae, Dan Balasescu, David Zhao, Dean Herbert, default0, Derrick Timmermans, Desconocidosmh, Dragicafit, Drew DeVault, Drezi126, DTSDAO, ekrctb, emu1337, Endrik, Fabian L, Fabian Lindgren, Fire937, Firmatorenio, frankhjwx, FreezyLemon, Fukashi13, Gabe Livengood, Gagah Pangeran Rosfatiputra, Ganendra Afrasya, Grrum, Hanamuke, Henry Lin, HoLLy, Huo Yaoyuan, ilsubyeega-desu, Ivan Pavluk, Jack Boswell, Jack Lee, Jack Scotson, JackLee9355, Jacob, Jacob Odgård Tørring, Jai Sharma, James58899, Jamie Taylor, Jan Jurzitza, Jarosław Zgierski, Jesse Myers, Jessica Meng, Jihoon, Jihoon Yang, JimmyC7834, John Neijzen, jorolf, Joseph Madamba, Joseph-Ramos-CMU, Justus Tumacder, jvyden, Kaleb, kamp, Keijia, Kelvin, KoziLord, kyekiller, Kyle Chang, Laica, LastExceed, Leon Gebler, Liam DeVoe, LiangXiang Shen, Lucas A., Maciej Sołtys, MafinBoy, Malox10, Marco Stephan, MATRIX-feather, Max, Max Hübner, MBmasher, McEndu, Mikal Stordal, MillhioreF, miterosan, Morguldir, Moritz Bender, n4b3l, Nabile Rahmani, Naeferith, naoey, Nathan Alo, Nathan Du, Naxess, nwabear, ocboogie, odgaard, Olle Kelderman, Opelkuh, Owen Young, Pasi4K5, Patrick Andersson, Paul Teng, PercyDan, phos, Piotrek Brzeziński, Poliwrath, Power Maker, Poyo, ProgrammaticNajel, ProTheory8, qwewqa, recapitalverb, RedMindZ, rednir, Remie Richards, RizonFTW, Robin Avery, Ron B, Ronnie Moir, RORIdev, roridev, Ryan Zmuda, Salman Ahmed, Samuel Cattini-Schultz, Samuel Huang, Santeri Nogelainen, Sebastian Krajewski, Seth, Shane Woolcock, Shawdooow, Shivam, StanR, su, Sunghwan Bang, Susko3, Swords, tgi, TheOmyNomy, ThePyrotechnic, Thomas Müller, Thomas Tan, Tim Nolte, Tim Oliver, Tom Arrow, TPGPL, Tyler, UselessToucan, Vidalee, Viktor Rosvall, Vincent Maggioli, VINXIS, Vladimir Pavlov, voidedWarranties, vperus, wildtree, Willy Tu, Xexxar, Yao Chung Hu, Инсур

Homepage: www.other-life.com
Inspiration: Eternal Lands
Download: www.other-life.com/downloads.php
Developers: Alexander Gottwald, Felix Janda, Gé Vissers, Joe "Flame" Sullivan, Karol, Paul Broadhead (bluap in EL), Sir-Odie, xaphier

Homepage: metasepia.icecavern.net/OurPersonalSpace/index.html
Developers: Andrea Landaker, Rachel

Homepage: ospace
Developers: Aina Melkor, Anderuso, Marek Haičman, Mental, PeS, Qark, Random Chaos, Sindel, Vladimir Meister

Homepage: forum.outpost2.net/index.php/topic,5718.0.html
Inspiration: Outpost
Developers: belgianguy, Brett, cugone, Daniel Stevens, Leeor Dicker, Robert Toth

Homepage: elnormous/ouzel
Developers: Elviss Strazdins, Marlin Watts-Woods

Homepages: overgod, www.allegro.cc/depot/Overgod
Download: overgod/files
Developer: Linley Henzell

Homepage: i-love-kfc/xray-oxygen
Inspiration: XRay engine
Developers: Alex, Anton Kovalev, Anton Tsukanov, Borshig, Collectioner, darkhpp, ForserX, Georgiy-Timoshin, Giperion, Graff46, Ilya, Kozlov Dennis, Krodin, LtPetrov, Mortan, mrmnwar, qweasdd136963, RainbowZerg, Seakad, shriveledDude, Unfainthful, Viнt@rь, Vlad, Xottab_DUTY, Пётр