OpenKore Runtime
Unrated.
Dec 25, 2011 - v0.0.1.0multiple/multiple
OpenLara
Dec 9, 2018 - v0.3.0.06Game/ActionGame
OpenLieroX
Dec 31, 2015 - v0.0.58.3Game/ActionGame
OpenMortal
Oct 26, 2014 - v0.7.0.01Game/ArcadeGame
openMSX_PND
Nov 26, 2011 - v0.2.0.0Game/Emulator
openPirates
Unrated.
Dec 31, 2015 - v0.0.2.9Game/StrategyGame
OpenRA
Oct 20, 2017 - v1.0.0.05Game/StrategyGame
OpenRedAlert
Apr 21, 2011 - v426.0.0.1Game/StrategyGame
OpenSonic
Feb 6, 2013 - v1.3.1.0Game
OpenSSN
May 2, 2018 - v1.4.20130522.1Game/Simulation
Opentitus
Mar 29, 2012 - v1.0.0.0Game/ArcadeGame
OpenTTD
May 1, 2018 - v1.8.0.0Game/StrategyGame
OpenTyrian
Feb 11, 2014 - v2.2.1.2Game/ArcadeGame
OpenXcom
Jul 19, 2018 - v1.0.0.13Game/StrategyGame
OpenYahtzee
Nov 18, 2012 - v1.9.0.02Game/BoardGame
Operation Fenix
Dec 14, 2011 - v0.2.1.1Game/ArcadeGame
Opsu!
Oct 23, 2017 - v0.16.0.11Game/ActionGame
Orbit-Hopper
Aug 28, 2014 - v1.16.c.1Game/ArcadeGame
Orbital Eunuchs Sniper
Aug 2, 2014 - v1.30.0.01Game/ActionGame
Order of Twilight
Dec 15, 2013 - v1.0.0.01Game/ArcadeGame
Otho Robot
Jun 2, 2014 - v1.0.0.01Game/LogicGame
Otto Matic
Oct 1, 2022 - v4.0.0.01Game/ActionGame
Out of Order
Sep 29, 2015 - v1.0.0.01Game/AdventureGame
Overgod
May 22, 2011 - v1.0.0.0Game/ArcadeGame
P-UAE
Unrated.
Dec 31, 2015 - v1.6.10.1Game/Emulator