| Region | Title | System | Version | Edition | Languages | Serial | Status |
|---|
 | The Oregon Trail 4th Edition (Disc 1) | PC | 1.1 | Rerelease |  | OTF744BE-CD1 | ![2 and more dumps from original media [!]](/images/status/green.png "2 and more dumps from original media [!]") |
| The Oregon Trail 4th Edition (Disc 1) | PC | 1 | Original | | OTF744AE-CD1 |  |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | 1.2 | Original | | OTA744BE-CD3 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | | Original | | OTA744AE-CD3 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 2) | PC | 1.2 | Original | | OTA744BE-CD2 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 2) | PC | | Original | | OTA744AE-CD2 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.2a | Bundle Version Compaq Presario OEM | | | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.2 | Rerelease | | OTA744BE-CD1 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.0 | Original | | OTA744AE-CD1 | |
 | Ore no Shita de Agake
俺の下であがけ | PC | System3.9 Ver.5.43 | Original |  | ALB-005 | |
 | Orda: Severnyj veter
Орда: Северный ветер | PC | | Original |  | | |
| Orchid Technology Kelvin MPEG Software Catalog | PC | | | | | |
| Optimum Resource Sampler | PC | | Original | | | |
| Optimum Resource Sampler | PC | | Rerelease | | | |
| Opsys | PC | | Original | | | |
 | Opsys | PC | | 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) | | JCPL11, S0026179, S0026696, S0026707 | |
| 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 2) (In the Lounge with No One Lives Forever) | PC | | Bundle Version Micro-Star International OEM |     | CD-W581995-MSYZ2 | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.004 | Game of the Year Edition | | | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.0 | Original | | | |
| The Operative: No One Lives Forever (Disc 1) | PC | | Bundle Version Micro-Star International OEM | | CD-W581995-MSYZ1, FXX08903223D1 | |
| The Operative: No One Lives Forever (Disc 1) | PC | | Game of the Year Edition | | | |
 | The Operative: No One Lives Forever (Disc 1) | PC | 1.004 | Game of the Year Edition (BestSeller Series) | | S0026706 | |
| The Operative: No One Lives Forever (Disc 2)
ノーワンリブスフォーエバー | PC | 1.004, 1.004J | Original | | | |
| The Operative: No One Lives Forever (Disc 1)
ノーワンリブスフォーエバー | PC | 1.004, 1.004J | Original | | | |
 | 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 2) | PC | 1.004 | Game of the Year Edition | | S0025037 | |
| The Operative: No One Lives Forever (Disc 2) | PC | 1.0 | Original | | FXX08903223D2 | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.004 | Game of the Year Edition | | S0025036 | |
 | The Operative: No One Lives Forever (Disc 1) | PC | 1.004 | Game of the Year Edition (BestSeller Series) | | JCPL11, S0026695 | |
| The Operative: No One Lives Forever (Disc 2) | PC | 1.0 | Original | | FXX08903223D2 | |
| 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 1) | PC | 1.0 | Original | | FXX08903223D1 | |
| The Operational Art of War: Vol. 1: 1939-1955 | PC | | | | | |
| The Operational Art of War: Century of Warfare | PC | | Original | | | |
| The Operational Art of War II: Modern Battles 1956-2000 | PC | 1.0 | Original | | | |
| The Operational Art of War II: 1956-2000
The Operational Art of War II: Bewaffnete Konflikten | PC | | Original | | | |
 | The Operational Art of War II | PC | 1.01.02 | Xplosiv | | EI-1259-3 | |
| Operation: Surgery Has Never Been so Silly! | PC | | Sold Out Software | | | |
| Operation: Surgery Has Never Been so Silly! | PC | | Replay Kids | | OPERPCREGB/A | |
| Operation Neptune | PC | 1.23 | The ClueFinders: Math Ages 9-12 | | ONT744EE-CD | |
| Operation Neptune | PC | 1.22 | Original | | ONT744CE-CD | |
| Operation Mania | PC | 1.0.5.64r | Original | | 1912507 | |
| Operation Flashpoint: Soprotivlenie
Operation Flashpoint: Сопротивление | PC | 1.85 | | | | |
| Operation Flashpoint: Resistance | PC | 1.75 | Original | | MOFRCDUS00 | |
| Operation Flashpoint: Resistance | PC | 1.75 | Original |  | MOFRCDEU00 | |
| Operation Flashpoint: Holodnaja vojna
Операция Flashpoint: Холодная война | PC | 1.46 | Original | | | |
| Operation Flashpoint: Gold Upgrade | PC | 1.30 | Original, Gold Edition | | MOFUCDEU00, MOFUCDUS00 | |
 | Operation Flashpoint: Gold Upgrade
Operace Flashpoint: Gold Upgrade | PC | | Original |  | | |
| Operation Flashpoint: Cold War Crisis | PC | | Playable Demo | | POPFCDUS40 | |
| Operation Flashpoint: Cold War Crisis | PC | 1.0 | Original, Gold Edition | | MOPFCDEU00 | |
| Operation Combat II | PC | 1.0 | Action CD-ROM 5 Pak | | | |
| Operation Body Count: One Level Preview | PC | | Original | | | |
| Operation Blockade | PC | | Original | | 04-23965CD | |
| Operation Barbarossa: The Struggle for Russia | PC | | Original | | | |
| Operation | PC | | General Mills | | AM801R5 | |
 | Operacja Pustynny Grom / The Partners | PC | | Covermount | | | |
| Operaciya Silent Storm: Chasovye (Disc 2)
Операция Silent Storm: Часовые | PC | | 1C: Igroteka | | | |
| Operaciya Silent Storm: Chasovye (Disc 1)
Операция Silent Storm: Часовые | PC | | 1C: Igroteka | | | |
| Operaciya Silent Storm (Disc 2)
Операция Silent Storm | PC | Aug 11 2003 | 1C: Igroteka | | | |
| Operaciya Silent Storm (Disc 1)
Операция Silent Storm | PC | Aug 11 2003 | 1C: Igroteka | | | |
| Operaciya "X" ili novye piklyucheniya Shuricha (Disc 1)
Операция "Х" или новые приключения Шурича | PC | | 1C: Kollekciya igrushek | | | |
| Operaciya "Plastilin" (Disc 2)
Операция "Пластилин" | PC | | 1C: Kollekciya igrushek | | | |
| Operaciya "Plastilin" (Disc 1)
Операция "Пластилин" | PC | | 1C: Kollekciya igrushek | | | |
| Operaciya "Blau"
Операция "Блау" | PC | | Original | | | |
| Operaciya "Barbarossa"
Операция "Барбаросса" | PC | | Original | | | |
| Opera House Preview Disc
オペラハウス プレビューディスク | PC | | Original | | | |
| Opera Fatal | PC | | Tandem | | 1444 | |
| Opera Fatal | PC | | Original | | | |
| Opening Night: Behind The Scenes | PC | 1.0 | Original | | #HCD646B | |
| Opening Night | PC | 1.0 | Original | | #HCD646A | |
 | Open Season (Disc 1) | PC | 1.00 | Original |  | | |
 | Open Season
Boog & Elliot | PC | 1.0 | Demo |    | | |
| Open Season (Disc 3)
Сезон Охоты | PC | | Original | | | |
| Open Season (Disc 2)
Сезон Охоты | PC | | Original | | | |
| Open Season (Disc 1)
Сезон Охоты | PC | | Original | | | |
| Open Season (Disc 3) | PC | | Original | | 5004905-CD 3 | |
| Open Season (Disc 2) | PC | | Original | | 5004905-CD 2 | |
| Open Season (Disc 1) | PC | | Original | | 5004905-CD 1 | |
 | Open Season (Disc 3) | PC | 1.00 | Original | | 5004904-CD 3 | |
| Open Season (Disc 2) | PC | 1.00 | Original | | 5004904-CD 2 | |
| Open Season (Disc 1) | PC | 1.00 | Original | | 5004904-CD 1 | |
 | Open Season
Les Rebelles de la Forêt | PC | | Cheese Heads | | | |
| Open Kart | PC | | I Videogiochi del "Giornalino" | | | |
 | Op Avontuur in het Piratenschip | PC | | Original | | 5989 | |
| Op Avontuur in de Vuurtoren | PC | | Original | | 5990 | |
| Op Avontuur in de Molen | PC | | Original | | 5991 | |
| Oozora ni Kodawarou! Minna no Kuukou 2
大空にこだわろう！ みんなの空港２ | PC | | | | | |
| Ontdek de Boerderij met Barabas de Boekenbij | PC | | Original | | | |
| Onsen Ryokou Kakumei: Ich liebe dich.!
温泉旅行革命 ～Ｉｃｈ ｌｉｅｂｅ ｄｉｃｈ．！～ | PC | 1.00 | Original | | RUCCA-003 | |
| Onsen Ping-Pong
温泉卓球 | PC | | Event Oyobi Tsuushin Hanbaiban | | | |
| Onsen de Takkyuu
温泉ｄｅ卓球 | PC | | Original | | | |
| Onsalakorv | PC | | Original | | | |
| Only You: Sekai no Namida to Shoujo no Hanashi: Prelude
Ｏｎｌｙ Ｙｏｕ －世界の涙と少女のハナシ－ Ｐｒｅｌｕｄｅ | PC | 1.00 | Trial Edition version:share II | | | |
| Only One 2: Naomi: Ai no Inori ga Todoku Toki
オンリーワン２ なおみ 愛の祈りが届く時 | PC | 1.0.0.1 | Original | | ON2-NAO | |
| Only One 2: Bijin Casino Dealer Hitomi: Sei no Roulette
オンリーワン２ 美人カジノディーラー瞳 性のルーレット | PC | | Original | | ON2-HITO | |
| Only One + R: Higyaku no Mermaid Minano
オンリーワン＋Ｒ ～被虐のマーメイド美奈乃～ | PC | | Original | | | |
| Only Fun: Entra anche tu nel mondo dei Videogames | PC | | | | | |
| Online G@mer n. 5: Juin/Juillet 2001 (Disc 1) | PC | | | | | |
