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
OptiTask
Apr 8, 2013 - v0.9.0.0Office
Oragir
Unrated.
Mar 28, 2013 - v1.0.0.0Office