| Region | Title | System | Version | Edition | Languages | Serial | Status |
|---|
 | Operation Flashpoint: Dragon Rising | PC | | Original |      | MOFP2CDEU00 | ![2 and more dumps from original media [!]](/images/status/green.png "2 and more dumps from original media [!]") |
 | Operation Flashpoint: Red River | PC | 1.0 | Original | | MOFP3CDEU00 | |
| Outcast (Disc 1) | PC | | Original | | OUTCAPC52G/A1 | |
 | Operation | PC | | General Mills | | AM801R5 | |
 | Obscure
ObsCure | PC | 1.1 | Covermount | | | |
| The Operative: No One Lives Forever (Disc 2)
In the Lounge with No One Lives Forever | PC | 1.0 | Original | | | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.0 | Original | | | |
| Oni | PC | 1.0 | Original | | | |
| Onimusha 3 | PC | | Original | | 5004561 | |
| Odium
ōdi·um | PC | | Original | | CD-W58-1104-0 | |
| Olympic Soccer | PC | | CD-ROM Classic Collection 2 | | | |
 | Overwatch | PC | | Origins Edition, Legendary Edition |       | 73052101EU | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.1 | Rerelease, Southwestern School Set | | 380859B-CD | |
| The Operative: No One Lives Forever (Disc 1) | PC | | Game of the Year Edition | | | |
| OutRun 2006: Coast 2 Coast (Disc 2) | PC | | Original | | | |
| OutRun 2006: Coast 2 Coast (Disc 1) | PC | | Original | | | |
 | One Must Fall 2097
One Must Fall | PC | | Covermount | | D.L.: M-8684-97 | |
| One Unit Whole Blood | PC | 1.21 | Original | | 04-16459CD1 | |
 | The Operative: No One Lives Forever (Disc 2) | PC | 1.004 | Game of the Year Edition | | S0025037 | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.004 | Game of the Year Edition | | S0025036 | |
| The Operational Art of War: Century of Warfare | PC | | Original | | | |
| Overlord | PC | | Original | | MOVL1CDEU00 | |
| Operation Flashpoint: Dragon Rising | PC | 1.0 | Original | | MOFP2CDEU00 | |
 | Operaciya "Plastilin" (Disc 2)
Операция "Пластилин" | PC | | 1C: Kollekciya igrushek | | | |
| Operaciya "Plastilin" (Disc 1)
Операция "Пластилин" | PC | | 1C: Kollekciya igrushek | | | |
 | The Operative: No One Lives Forever (Disc 2) | PC | 1.004 | Game of the Year Edition, Game of the Year Edition (BestSeller Series), Game of the Year Edition (Covermount) | | JCPL11, S0026179, S0026696, S0026707 | |
| Outcast | PC | | DVD-ROM |  | | |
| Outpost | PC | 1.5 | Rerelease, SierraOriginals | | | |
 | Over 10 Tetrix Games | PC | | Original | | | |
| OutRun 2006: Coast 2 Coast | PC | 1.00.0000 | Serie Maxima II | | SEGA-PC029 | |
| Oregon Trail II | PC | 1.0 | Original | | | |
 | Operacja Pustynny Grom / The Partners | PC | | Covermount | | | |
| Over 1000 Games: The Complete Encyclopedia of Games (Disc 2) | PC | | Rerelease | | | |
| Over 1000 Games: The Complete Encyclopedia of Games (Disc 1) | PC | | Rerelease | | | |
| The Omega Stone: Riddle of the Sphinx II (Disc 4) | PC | 1.2.3.2 | Original | | | |
| The Omega Stone: Riddle of the Sphinx II (Disc 3) | PC | 1.2.3.2 | Original | | | |
| The Omega Stone: Riddle of the Sphinx II (Disc 2) | PC | 1.2.3.2 | Original | | | |
| The Omega Stone: Riddle of the Sphinx II (Disc 1) | PC | 1.2.3.2 | Original | | | |
| O.D.T. | PC | | Original | | | |
| Overboard! | PC | | Dice | | DCG 005752, DMM 005776 | |
| Obratnyj otschet
Обратный отсчет | PC | v.1 1.06.10.22 | Original | | | |
 | Oil Tycoon | PC | 1.01 | Original | | | |
 | Outlaws (Disc 2)
アウトロー | PC | 1.0 Build 3 | Original | | 9511831 | |
| Outlaws (Disc 1)
アウトロー | PC | 1.0 Build 3 | Original | | 9511830 | |
| Owlboy | PC | 0.0.6152.604 | IndieBox | | | |
| Outlaws: Die Gesetzlosen (Disc 1) | PC | 1.1 | Rerelease | | | |
| Outlaws: Die Gesetzlosen (Disc 2) | PC | 1.1.1 | Rerelease | | | |
 | Ori and the Blind Forest: Definitive Edition | PC | 5.3.2.9582331 | Original, Limited Edition | | | |
 | Original War (Disc 2) | PC | | Original, Gamer Collector | | | |
| Original War (Disc 1) | PC | | Original, Gamer Collector | | | |
| The Orange Box (Disc 2) | PC | | Original, EA Value Games | | VAD07705811D2 | |
| The Orange Box (Disc 1) | PC | | Original, EA Value Games | | VAD07705811D | |
| Oni | PC | 1.0 | Original | | | |
| Outlaws (Disc 2) | PC | | M6 Multimedia | | M6IMM6 | |
| Outlaws (Disc 1) | PC | | M6 Multimedia | | M6IMM6 | |
| Outcast (Disc 2) | PC | | Play the Games Vol. 3 | | | |
| Outcast (Disc 1) | PC | | Play the Games Vol. 3 | | | |
| Outcast (Disc 1) | PC | | Limitierte Sonderausgabe | | OUTCAPC520/A1 | |
| The Orange Box (Disc 2) | PC | 4295 / 4539 | Rerelease |         | | |
| The Orange Box (Disc 1) | PC | 4295 / 4539 | Rerelease | | | |
| Obscure
ObsCure | PC | | Original | | 71902134 | |
| Obscure
ObsCure | PC | | Software Pyramide | | | |
| Obscure II
ObsCure II | PC | 1.0 | Covermount | | | |
| Obscure II
ObsCure II | PC | 1.0.0.0 | Original | | | |
| Operation Flashpoint: Gold Upgrade | PC | 1.30 | Original, Gold Edition | | MOFUCDEU00, MOFUCDUS00 | |
| Odell Down Under | PC | | Original, SoftKey | | POD544AE-CD | |
| Official Sega Dreamcast Magazine: Special Edition Preview PC CD-ROM | PC | | | | | |
| Die Original Moorhuhn Jagd | PC | | Best of Moorhuhn | | | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Original | | IB2G-ODDG5 | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.004 | Game of the Year Edition (BestSeller Series) | | JCPL11, S0026695 | |
| Official Formula 1 Racing | PC | | Original | | | |
| Operation Flashpoint: Resistance | PC | 1.75 | Original | | MOFRCDEU00 | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Original | | 04-12608CD | |
| Oregon Trail II | PC | 1.31 | Rerelease | | HCD744BE-CD | |
| The Orange Box (Disc 2) | PC | | Original | | 985217 | |
| The Orange Box (Disc 1) | PC | | Original, EA Classics | | 985207, VAE07705811D, VAE07705811D/ENG, VAE07707118D/ENG, VAX07705811D/AUS | |
| Obsidian (Disc 5) | PC | | Original | | | |
| Obsidian (Disc 4) | PC | | Original | | | |
| Obsidian (Disc 3) | PC | | Original | | | |
| Obsidian (Disc 2) | PC | | Original | | | |
| Obsidian (Disc 1) | PC | | Original | | | |
| Orion Burger | PC | | Gold Games 2 (CD 11) | | SPI 046 | |
| The Orange Box (Disc 2) | PC | | Original | | VAI07705811D2 | |
| The Orange Box (Disc 1) | PC | | Original | | VAI07705811D | |
| Obsidian (Disc 5) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 4) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 3) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 2) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 1) | PC | | Original, Complimentary Copy | | 11008 | |
| Outlaws (Disc 1) | PC | 1.0 Build 3 | Bundle Version Diamond OEM | | 644430 | |
| Oscar | PC | | Jackson Libri | | | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.004 | Game of the Year Edition (BestSeller Series) | | S0026178 | |
| The Operative: No One Lives Forever (Disc 2) | PC | 1.0 | Original | | FXX08903223D2 | |
| Outlaws (Disc 2) | PC | 2.0 | Rerelease | | 9511831 | |
| Outlaws (Disc 1) | PC | 2.0 | Rerelease | | 9511830 | |
| Outpost 2: Geteilte Bestimmung | PC | 1.0 | Original | | S0011248 | |
| Oregon Trail II | PC | 1.31 | Rerelease | | #HCD744AE-CD | |
| Otverzhennye: Tajna temnoj rasy (Disc 1)
Отверженные: Тайна темной расы | PC | | 1C: Igrushki | | SNOW OT21 0110 IR | |
| Ob"ekt 69: Mest' Krassera
Объект 69: Месть Крассера | PC | | Original | | | |
| Ob"ekt 69: Kasablanka
Объект 69: Касабланка | PC | | Original | | RUSSOBIT-M 2003/408 | |
