| Region | Title | System | Version | Edition | Languages | Serial | Status |
|---|
 | ObsCure | PC | | Original |   | 71902134 | ![2 and more dumps from original media [!]](/images/status/green.png "2 and more dumps from original media [!]") |
| ObsCure | PC | | Software Pyramide | | | |
 | ObsCure II | PC | 1.0.0.0 | Original |  | | |
 | Oddworld: Abe's Exoddus (Play Disc) | PC | 2.0 | Budget, Covermount |  | MMICDR 5280 | |
| Oddworld: Abe's Exoddus (Install Disc) | PC | 2.0 | Original | | | |
| Oddworld: Abe's Exoddus (Play Disc) | PC | 2.0 | Original | | | |
 | Oddworld: Abe's Exoddus (Installazione) | PC | 1.0 | Replay |  | ABEXPCREI/A1 | |
| Oddworld: Abe's Exoddus (Gioco) | PC | 1.0 | Replay | | ABEXPCREI/A2 | |
 | Oddworld: Abe's Exoddus (Play) | PC | | Original | | 04-15993CD2 | |
| Oddworld: Abe's Exoddus (Install) | PC | 2.0 | Original | | 04-15993CD1 | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Original | | IB2G-ODD5 | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Original | | IB2G-ODDG5 | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Original | | 04-12608CD | |
| Odell Down Under | PC | | Original, SoftKey | | POD544AE-CD | |
| ODS Robot Challenge | PC | 5.0.1r26 | Teacher's Edition | | | |
| Odyssey: The Search for Ulysses (Disc 1) | PC | | Original | | ODY-ENCD1 | |
| Odyssey: The Search for Ulysses (Disc 2) | PC | | Original | | ODY-ENCD2 | |
| Official Formula 1 Racing | PC | | Original |  | | |
| The Official Guide to Babylon 5
The Official Guide to J. Michael Straczynski's Babylon 5 | PC | | Original | | | |
| Official Sega Dreamcast Magazine: Special Edition Preview PC CD-ROM | PC | | Magazine Bundle | | | |
 | Oil Tycoon | PC | 1.01 | Original | | | |
 | Omar Sharif Bridge | PC | 1.0 | Original | | | |
| Omikron: The Nomad Soul (Disc 1) | PC | 1.0 | Original | | | |
| Omikron: The Nomad Soul (Disc 2) | PC | 1.0 | Original | | | |
| Omikron: The Nomad Soul (Disc 3) | PC | 1.0 | Original | | | |
| Ominous Horizons
Ominous Horizons: A Paladin's Calling | PC | 1.0 | Original | | | |
| One Unit Whole Blood | PC | 1.21 | Original | | 04-16459CD1 | |
 | Oni
奥妮 | PC | 1.7 | Original |  | | |
| Oni
Они | PC | 1.0 | | | | |
| Oni | PC | 1.0 | Original | | | |
| Open Season (Disc 1) | PC | | Original |  | 5004904-CD 1 | |
| Open Season (Disc 2) | PC | | Original | | 5004904-CD 2 | |
| Open Season (Disc 3) | PC | | Original | | 5004904-CD 3 | |
| Operation Flashpoint: Cold War Crisis | PC | 1.0 | Original, Gold Edition | | MOPFCDEU00 | |
 | Operation Flashpoint: Cold War Crisis | PC | | The Games Collection | | | |
| Operation Flashpoint: Cold War Crisis | PC | 1.0 | Original | | MOPFCDUS00 | |
| Operation Flashpoint: Gold Upgrade | PC | 1.30 | Original | | MOFUCDUS00 | |
 | Operation Flashpoint: Gold Upgrade | PC | 1.30 | Original, Gold Edition | | MOFUCDEU00, MOFUCDUS00 | |
| Operation Flashpoint: Holodnaja vojna
Операция Flashpoint: Холодная война | PC | 1.46 | Original | | | |
| Operation Flashpoint: Resistance | PC | 1.75 | Original | | MOFRCDUS00 | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.0 | Original |  | FXX08903223D1 | |
| The Operative: No One Lives Forever (Disc 2) | PC | 1.0 | Original | | FXX08903223D2 | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.0.0.4 | Game of the Year Edition: Covermount | | | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.0 | Original | | | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.004 | Game of the Year Edition | | | |
| The Operative: No One Lives Forever (Disc 2) | PC | 1.0 | Original | | | |
| 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 | | S0026179 | |
 | The Orange Box (Disc 2) | PC | | Original, EA Classics |     | VAE07707118D2/ENG, VAX07705811D2, VAX07705811D2/AUS | |
| The Orange Box (Disc 2) | PC | | Original | | 985217 | |
| The Orange Box (Disc 1) | PC | | Original, EA Classics | | 985207, VAE07705811D, VAE07707118D/ENG, VAX07705811D/AUS | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.0 | Original | | OTA744AE-CD1 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 2) | PC | | Original | | OTA744AE-CD2 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | | Original | | OTA744AE-CD3 | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.0 | Original | | 380859-CD | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.1 | Rerelease, Southwestern School Set | | 380859B-CD | |
| Oregon Trail II | PC | 1.3 | Smart Saver | | 381032-CD/i401ha | |
| Oregon Trail II | PC | 1.31 | Rerelease | | #HCD744AE-CD | |
| Oregon Trail II: 25th Anniversary Limited Edition | PC | 1.3 | Original, SoftKey | | #OTR744AE-CD | |
| The Oregon Trail | PC | 1.2 | Original | | #HCD706 | |
| The Oregon Trail | PC | 1.2 | Original | | #HCD706 | |
| The Original Links | PC | | Solid Gold Edition | | | |
| Orion Burger | PC | | Gold Games 2 (CD 11) | | SPI 046 | |
| Oscar | PC | | Original | | | |
| Outcast (Disc 1) | PC | | Original | | OUTCAPC52G/A1 | |
| Outcast (Disc 2) | PC | | Original | | OUTCAPC52G/A2 | |
| Outcast (Disc 1) | PC | | Original | | 42831-9110TC | |
| Outlaws (Disc 1) | PC | 1.0 | Original | | 9511830 | |
| Outlaws (Disc 1) | PC | 2.0 | LucasArts Classics | | 3000009.101.UK | |
| Outlaws (Disc 2) | PC | 1.0 | Original | | 9511831 | |
| Outlaws (Disc 2) | PC | 2.0 | LucasArts Classics | | 3000009.102.UK | |
 | Outlaws (Disc 1) | PC | | Original | | | |
| Outlaws (Disc 2) | PC | | Original | | | |
| Outlaws (Disc 1) | PC | 1.0 | Original | | | |
| Outlaws (Disc 2) | PC | 1.0 | Original | | | |
| Outlaws (Disco 1) | PC | 2.0 | Collezione CD-Rom by C.T.O. | | LUC628 | |
| Outlaws (Disco 2) | PC | 2.0 | Collezione CD-Rom by C.T.O. | | LUC628 | |
| Outlaws (Disc 1) | PC | 1.0 Build 3 | Original | | 9511830 | |
| Outlaws (Disc 1) | PC | 2.0 | Rerelease | | 9511830 | |
| Outlaws (Disc 1) | PC | 2.0 | Rerelease | | 9511830 | |
| Outlaws (Disc 2) | PC | 1.0 Build 3 | Original | | 9511831 | |
| Outlaws (Disc 2) | PC | 2.0 | Rerelease | | 9511831 | |
| Outlaws (Disc 2) | PC | 2.0 | Rerelease | | 9511831 | |
| Outlive | PC | 1.01 | Original | | | |
| Outpost | PC | | Original | | S725430 | |
| Outpost | PC | 1.5 | Rerelease, Sierra Originals | | | |
| Outpost 2: Divided Destiny | PC | 1.2.0.5 | Original | | | |
| OutRun 2006: Coast 2 Coast | PC | | Gamer's Choice | | THQ70690 | |
| OutRun 2006: Coast 2 Coast | PC | 1.0 | Original | | SEGA-PC029 | |
| OutRun 2006: Coast 2 Coast | PC | 1.00.0000 | Serie Maxima II | | SEGA-PC029 | |
| Outward | PC | | Day One Edition | | 1024669LAINT, 103699 | |
| Outwars (Disc 1) | PC | 1.0 | Original | | 0298 Part No. X03-63527 | |
| Outwars (Disc 2) | PC | 1.0 | Original | | 0298 Part No. X03-57509 | |
| Over 1000 Games: The Complete Encyclopedia of Games (Disc 1) | PC | | Original | | | |
| Over 1000 Games: The Complete Encyclopedia of Games (Disc 2) | PC | | Original | | | |
| Overboard! | PC | | Original | | | |
| Overboard! | PC | | Dice | | DCG 005752, DMM 005776 | |
