| title | developer | year | platform | | pop. |
|---|
| Ocarina of Power | author | 2002 | Linux | adventure | image | | label | |
| OpenDungeons | Open Dungeons Community | 2009 | Linux | strategy | | subject | label | |
| OpenDungeons | Open Dungeons Community | ? | BSD | strategy | | | label | |
| OpenDungeons | Open Dungeons Community | ? | BSD | strategy | | | label | |
| OpenQuartz | Open Quartz Team | 2001 | Linux | shooter | | subject | label | |
| OpenQuartz | Open Quartz Team | ? | BeOS | shooter | | | label | |
| Operation Smash | author | 2013 | Linux | platformer Science Fiction | | subject | label | |
| OQPlus | author | ? | Linux | shooter | | | label | |
| OQPlus | ? | ? | BeOS | shooter | | | label | |
| Ori and the Blind Forest | Moon Studios | 2016 | Linux | platformer Fantasy | | | label | |
| Ori and the Blind Forest | Moon Studios | 2015 | Windows | platformer Fantasy | image | | label | |
| Ori and the Blind Forest: Definitive Edition | Moon Studios | 2016 | Windows | platformer Fantasy | image | subject | label | |
| ORiGiN | author | 2007 | Linux | action/reflex adventure Fantasy | image | subject | label | |
| OS2Moria | author | 1992 | OS/2 | role-play Fantasy | | | label | |
| Painkiller | People Can Fly | 2004 | Windows | shooter Fantasy | image | | label | |
| Painkiller: Overdose | Mindware Studios | 2007 | Windows | Fantasy | image | subject | label | |
| Path of Shadows | author | 2012 | Linux | role-play Fantasy | image | | label | |
| Penumbra: Necrologue | CounterCurrent Games | 2015 | Linux | adventure Horror | | | label | |
| pid | Might and Delight | 2012 | Windows | platformer | image | | label | |
| Pillars of Eternity | Obsidian Entertainment | 2015 | Windows | role-play Fantasy | image | subject | label | |
| Plok! | Tradewest | 1993 | SNES | platformer | image | | label | |
| Poncho | Delve Interactive | 2015 | Linux | platformer puzzle Science Fiction | | | label | |
| Portal 2 | Valve | 2011 | Windows | action/reflex puzzle Science Fiction | image | subject | label | |
| Prehistorik 2 | Titus | 1993 | MS-DOS | platformer Humorous | image | | label | |
| Prehistorik 2 | Titus | 2015 | Linux | platformer Humorous | | | label | |
| Prey | Arkane Studios | 2017 | Windows | shooter Science Fiction | image | | label | |
| Primal | SCE Studio Cambridge | 2003 | PS2 | beat 'em up adventure Fantasy | image | subject | label | |
| Prince of Persia: The Forgotten Sands | Ubisoft Montreal | 2010 | Windows | action/reflex adventure Fantasy | image | subject | label | |
| Princess Rescue | Author | 2013 | Atari 2600 | platformer Fantasy | image | | label | |
| Project Paradise | Soft Enterprises | 1997 | MS-DOS | action/reflex Science Fiction | | | label | |
| Project Warlock | Buckshot Software | 2018 | Windows | action/reflex Fantasy | image | | label | |
| Puggsy | Traveller's Tales | 1993 | Mega Drive | platformer Cartoon | image | | label | |
| Puggsy | Traveller's Tales | 1994 | Amiga | platformer puzzle Cartoon | image | | label | |
| Puggsy | Traveller's Tales | 1993 | Mega-CD | platformer Cartoon | image | | label | |
