OpenRTS
OpenRW
Open Season
Nintendo GameCube, PlayStation Portable, PlayStation 2, and 5 more
Ubisoft Montreal
Open Sonic
Open Sorcery
macOS, Windows, Linux, and 1 more
Open Sorcery: Sea++
Linux, macOS, Windows
Open Space 2D
Windows
Open The Door
OpenTTD
Android, macOS, Windows, and 1 more
Ludvig Strigeus
OpenTyrian
macOS, Linux, Windows
Open Wheel Manager
Open World Foreva
OpenXcom
Windows, Linux
Operacja Wąż Morski
Opera Fatal
Windows, Mac OS
Braingame Publishing
Operation
Operation 7
Operation7
iOS, Windows, Linux
Francisco Antonio
Operation8 Project
Operation Abyss: New Tokyo Legacy
Windows, PlayStation Vita
Operation Air Assault
PlayStation 2
Naps Team
Operation Airsoft Beta
Operation Apocalypse
Apple II
Operation Armstrong
Operation Babel: New Tokyo Legacy
PlayStation Vita, Windows
Operation Bagration
Wargaming.net
Operation Barbarossa – The Struggle for Russia
Operation: Black Mesa
Operation: Blockade
Operation Body Count
Windows, Disk Operating System
Capstone Software
