| Region | Title | System | Version | Edition | Languages | Serial | Status |
|---|
 | Oil Rush | PC | | Original |    | |  |
| Oil Tycoon 2 | PC | | Original | | | |
| Oktoberfest Wiesn-Gaudi | PC | 1.0 | Original | | | |
| OMSI Add-on: Wien: Der Hochflurbus LU 200 | PC | 1.0 | OMSI Bundle | | | |
| OMSI: Der Omnibussimulator | PC | 1.04 | OMSI Bundle | | | |
| Oni | PC | 1.0 | Green Pepper |  | | |
 | The Operative: No One Lives Forever (Disc 1) | PC | 1.0 | Original | | | ![2 and more dumps from original media [!]](/images/status/green.png "2 and more dumps from original media [!]") |
| The Operative: No One Lives Forever (Disc 2) | PC | 1.0 | Original | | | |
| Die Original Moorhuhn Jagd | PC | | Best of Moorhuhn | | | |
| Osterspiele-Box
Oster Spielebox | PC | | Original | | | |
 | Operation Flashpoint: Dragon Rising | PS3 | 01.01 | Original, Promo |   | BLES-00597 | |
 | Ookami: Zekkeiban
大神 絶景版 | PS3 | 00.00 | Original, PlayStation 3 the Best, PlayStation 3 the Best (Reprint) |  | BLJM 55061 … | |
 | Operation Flashpoint: Dragon Rising | PS3 | 01.01 | Original | | BLJM 60152 | |
| Operation Flashpoint: Red River | PS3 | 01.02 | Original, Codemasters the Best | | BLJM 60361 … | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.0 | Original |  | FXX08903223D1 | |
| Operation Flashpoint: Resistance | PC | 1.75 | Original | | MOFRCDEU00 | |
 | Operation Flashpoint: Gold Upgrade | PC | 1.30 | Original, Gold Edition | | MOFUCDEU00, MOFUCDUS00 | |
| Operation Flashpoint: Cold War Crisis | PC | 1.0 | Original, Gold Edition | | MOPFCDEU00 | |
| Outpost 2: Geteilte Bestimmung | PC | 1.0 | Original | | S0011248 | |
| OutRun 2006: Coast 2 Coast | PS2 | 1.02 | Original | | SLES-53998 | |
| Otousan no Tame no Tsuri: Fly Fishing-hen
お父さんのための釣り フライ フィッシング編 | PC | | Original | | TFF-058-1 | |
| Oumagatoki: Kaidan Romance
逢魔時 ～怪談ロマンス～ | PSP | 1.02 | Original | | ULJM 06039 | |
