| Region | Title | System | Version | Edition | Languages | Serial | Status |
|---|
 | Obscure (Disc 3)
惊悚空间 | PC | 1.0 | Original |  | |  |
| Obscure (Disc 4)
惊悚空间 | PC | 1.0 | Original | | | |
 | Odyssey (Disc 1)
奧德賽 | PC | | Original | | | |
| Odyssey (Disc 2)
奧德賽 | PC | | Original | | | |
| Olympiad Qiaosai 2
奧林匹亞橋賽2 | PC | | Original | | | |
| Oscar the Balloonist: Discovers the Farm
小小探險家奧斯卡 農場奇遇記 | PC | | Original | | | |
 | The Orange Box (Disc 1) | PC | 4295 / 4539 | Rerelease |                    | | ![2 and more dumps from original media [!]](/images/status/green.png "2 and more dumps from original media [!]") |
| The Orange Box (Disc 2) | PC | 4295 / 4539 | Rerelease | | | |
| The Orange Box (Disc 1) | PC | | Original | | | |
| The Orange Box (Disc 2) | PC | | Original | | | |
| Oni
奥妮 | PC | 1.7 | Original | | | |
 | Overwatch | PC | | Origins Edition, Legendary Edition | | 73052101EU | |
 | The Orange Box (Disc 1) | PC | | Original | | VAX07705811D | |
 | The Orange Box (Disc 1) | PC | | Original | | VAI07705811D | |
| The Orange Box (Disc 2) | PC | | Original | | VAI07705811D2 | |
| The Orange Box (Disc 1)
戰慄時空2：二部曲重裝旗艦版 | PC | | Original | | TTE0193 | |
| The Orange Box (Disc 2)
戰慄時空2：二部曲重裝旗艦版 | PC | | Original | | TTE0193 | |
 | 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 | |
| The Orange Box (Disc 2) | PC | | Original, EA Classics | | VAE07705811D2/ENG, VAE07707118D2/ENG, VAX07705811D2, VAX07705811D2/AUS | |
 | Operation Flashpoint: Gold Upgrade
Operace Flashpoint: Gold Upgrade | PC | | Original |  | | |
| Overlord II | PC | | Preview Code | | | |
 | Ollo in the Sunny Valley Fair | PC | | Original | | | |
| Open Season
Boog & Elliot | PC | 1.0 | Demo | | | |
| Olivers äventyr: Drakens förbannelse | PC | | Original | | 021120110 | |
 | Ontdek de Boerderij met Barabas de Boekenbij | PC | | Original | | | |
| Oscar the Balloonist and the Secrets of the Forest
Oscar de Ballonvaarder en de Geheimen van het Bos | PC | | Libelle | | | |
| Ollo en de Reuzentomaat | PC | | CD-ROM Toppers | | | |
 | Othello | PC | | Original | | | |
| Othello | PC | | Original | | 99011 | |
| Othello CD-ROM | PC | | Original | | | |
| Outcast | PC | | DVD-ROM | | | |
| Open Season (Disc 1) | PC | 1.00 | Original | | 5004904-CD 1 | |
 | Open Season (Disc 2) | PC | 1.00 | Original | | 5004904-CD 2 | |
| Open Season (Disc 3) | PC | 1.00 | Original | | 5004904-CD 3 | |
 | Open Season (Disc 1) | PC | 1.00 | Original | | | |
| Open Season (Disc 1) | PC | 1.0 | Original | | 683131-CD1 | |
| Open Season (Disc 2) | PC | 1.0 | Original | | 683131-CD2 | |
| Open Season (Disc 3) | PC | 1.0 | Original | | 683131-CD3 | |
| O.D.T. | PC | | Dice | | DCG 005509 | |
| O.D.T. | PC | | Original | | | |
| O.R.B: Off-World Resource Base | PC | 1.0 | Original | | 22434CD | |
| Obscure
ObsCure | PC | 1.0 | Original | | 719 02 102 | |
| Obscure (Disc 1)
ObsCure | PC | 1.0 | Original | | PCO457CD | |
| Obscure (Disc 2)
ObsCure | PC | 1.0 | Original | | PCO457CD | |
| Obscure (Disc 3)
ObsCure | PC | 1.0 | Original | | PCO457CD | |
| Obscure (Disc 4)
ObsCure | PC | 1.0 | Original | | PCO457CD | |
| Obscure (Disc 5)
ObsCure | PC | 1.0 | Original | | PCO457CD | |
| Obscure II
ObsCure II | PC | 1.0 | Covermount | | | |
 | Obsidian (Disc 1)
オブシディアン | PC | | Original | | INR-1003 | |
| Obsidian (Disc 2)
オブシディアン | PC | | Original | | INR-1002 | |
| Obsidian (Disc 3)
オブシディアン | PC | | Original | | INR-1002 | |
| Obsidian (Disc 4)
オブシディアン | PC | | Original | | INR-1002 | |
| Obsidian (Disc 5)
オブシディアン | PC | | Original | | INR-1002 | |
| Obsidian | PC | 1.0 | Demo | | | |
| Obsidian (Disc 1) | PC | | Original | | 11008 | |
| Obsidian (Disc 1) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 2) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 3) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 4) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 5) | PC | | Original | | 11008 | |
| Obsidian (Disc 5) | PC | | Original, Complimentary Copy | | 11008 | |
| Ocean/Infogrames Show Case December 1997 | PC | | | | | |
| Oceans Below | PC | | Bundle Version OEM | | RVL 13-004-059 Rev. A / 2198610-590002 / I 083100 | |
| Oddballz: Your Wacky Computer Petz | PC | 1.0 | Original | | CS090370 | |
 | Oddworld: Abe's Exoddus (Instalar) | PC | 2.0 | Original | | | |
| Oddworld: Abe's Exoddus (Jugar) | PC | 2.0 | 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 (Disc 1) | PC | 1.0 | Covermount | | | |
| Oddworld: Abe's Exoddus (Disc 2) | PC | 1.0 | Covermount | | | |
 | Oddworld: Abe's Exoddus (Installatie Disk) | PC | 2.0 | Budget | | MMICDR 5280 | |
| 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 | | 04-12608CD | |
| Oddworld: Abe's Origins | PC | | Limited Run Games | | | |
| Odell Down Under | PC | | Original, SoftKey | | POD544AE-CD | |
 | Odium
ōdi·um | PC | | Covermount | | | |
| Odium
ōdi·um | PC | | Original | | CD-W58-1104-0 | |
| ODS Air Explorer | PC | 5.0r134 | Teacher's Edition | | | |
| ODS Air Explorer | PC | 5.0r134 | Teacher's Edition | | | |
| ODS Amazing Art Corner | PC | 5.0r134 | Teacher's Edition | | | |
| ODS Carnival Math | PC | 5.0r134 | Teacher's Edition | | | |
| ODS Carnival Math | PC | 5.0r134 | Teacher's Edition | | | |
| ODS Robot Challenge | PC | | Original | | | |
| 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 | |
| Odyssey: The Search for Ulysses (Disc 1) | PC | | Original | | | |
| Odyssey: The Search for Ulysses (Disc 2) | PC | | Original | | | |
| Of Light and Darkness: The Prophecy (Disc 1) | PC | | Original | | CD-W95-166-E | |
| Of Light and Darkness: The Prophecy (Disc 2) | PC | | Original | | CD-W95-166-E | |
| Of Light and Darkness: The Prophecy (Disc 3) | PC | | Original | | CD-W95-166-E | |
| Of Light and Darkness: The Prophecy (Disc 1) | PC | | Original | | CD-C95-166-0 | |
| Of Light and Darkness: The Prophecy (Disc 2) | PC | | Original | | CD-C95-166-1 | |
| Of Light and Darkness: The Prophecy (Disc 3) | PC | | Original | | CD-C95-166-2 | |
| Of Light and Darkness: The Prophecy: Premonitions Disk | PC | | | | CD-C95-166-DM | |
| Off Limits: Cassiopeia | PC | | ROMWARE | | ROM 10100 | |
