Region | Title | System | Version | Edition | Languages | Serial | Status |
| O Xephteris Taxideuei stin Ellada Ο Ξεφτέρης ταξιδεύει στην Ελλάδα | PC | | Original | | | |
| O! Rety! Psoty Dudusia Wesołka | PC | | Playada Gier | | P_20265_03A_PL | |
| O.D.T. | PC | | Dice | | DCG 005509 | |
| O.D.T. | PC | | Original | | | |
| O.R.B: Off-World Resource Base | PC | | Covermount | | | |
| O'boy-jakten | PC | | Original | | | |
| Ob"ekt 69: Kasablanka Объект 69: Касабланка | PC | | Original | | RUSSOBIT-M 2003/408 | |
| Ob"ekt 69: Mest' Krassera Объект 69: Месть Крассера | PC | | Original | | | |
| Obitaemyj ostrov Обитаемый остров | PC | | Original | | | |
| Obitaemyj ostrov: Chuzhoj sredi chuzhix Обитаемый остров: Чужой среди чужих | PC | | Original | | | |
| Obitaemyj ostrov: Zemlyanin Обитаемый остров: Землянин | PC | | Original | | | |
| Oblivious Garden: Carmina Burana (Disc 2) (Music Disc) | PC | | Standard Edition | | | |
| ObsCure | PC | | Original | | 71902134 | |
| ObsCure (Disc 1) | PC | | Original | | | |
| ObsCure (Disc 2) | PC | | Original | | | |
| ObsCure (Disc 3) | PC | | Original | | | |
| ObsCure (Disc 4) | PC | | Original | | | |
| Obsidian (Disc 1) | PC | | Original | | | |
| Obsidian (Disc 2) | PC | | Original | | | |
| Obsidian (Disc 3) | PC | | Original | | | |
| Obsidian (Disc 4) | PC | | Original | | | |
| Obsidian (Disc 5) | PC | | Original | | | |
| 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 (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 Jewels | PC | | Red Rocks | | | |
| Ochazukenori: Kaiki!! Mushi Danshaku no Yakata 御茶漬海苔 怪奇!!蟲男爵の館 | PC | | Original | | | |
| Oct 15 2002 | PC | | Press Kit | | | |
| Oddworld: Abe's Exoddus (Play) | PC | | Original | | 04-15993CD2 | |
| Oddworld: Abe's Origins | PC | | Limited Run Games | | | |
| Odell Down Under | PC | | Original, SoftKey | | POD544AE-CD | |
| Odin Klik Один Клик | PC | | Original | | 301/2002 | |
| Odium ōdi·um | PC | | Original | | CD-W58-1104-0 | |
| Odlikas za Prvake Одликаш за Прваке | PC | | Original | | | |
| ODS Robot Challenge | PC | | Original | | | |
| Odyssee: Auf der Suche nach Odysseus (Disc 1) | PC | | Original | | ODY-GERCD1 | |
| Odyssee: Auf der Suche nach Odysseus (Disc 2) | PC | | Original | | ODY-GERCD2 | |
| Odyssey (Disc 1) 奧德賽 | PC | | Original | | | |
| Odyssey (Disc 2) 奧德賽 | PC | | Original | | | |
| 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 | | | |
| Of Light and Darkness: The Prophecy (Disc 2) | PC | | Original | | | |
| Of Light and Darkness: The Prophecy (Disc 3) | PC | | Original | | | |
| 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 | |
| Offensive | PC | | Original | | | |
| Offensive Offensive War: The Ultimate Strategical Combat Game | PC | | Covermount | | | |
| Official Formula 1 Racing | PC | | Original | | | |
| The Official Guide to Babylon 5 The Official Guide to J. Michael Straczynski's Babylon 5 | PC | | Original | | | |
| The Official Guide to The Daedalus Encounter: Companion Disc | PC | | Original | | | |
| Official Lara Croft: Real Life '99 Lara: Character Images | PC | | Press Kit | | | |
| Official Sega Dreamcast Magazine: Special Edition Preview PC CD-ROM | PC | | | | | |
| Offroad Off-Road Redneck Racing | PC | | Original | | ECD 000592K | |
| Ogallala: Das Kartenspiel für PC | PC | | Original | | ECD000799D 00031111-001 | |
| Ognisty Podmuch: Fire Captain (Disc 1) (Dysk Instalacyjny) | PC | | Covermount | | | |
| Ognisty Podmuch: Fire Captain (Disc 2) (Dysk z Grą) | PC | | Covermount | | | |
| Oh!PC 1998-nen 8-gatsu-gou Tokubetsu Furoku CD-ROM Oh!PC 1998年 8月号 特別付録CD-ROM | PC | | | | OHPC-9808 | |
| Oh!PC 1998-nen 9-gatsu-gou Tokubetsu Furoku CD-ROM Oh!PC 1998年 9月号 特別付録CDーROM | PC | | | | OHPC-9809 | |
| Ohio Distinctive Software Vol. I | PC | | | | | |
| Oil Rush | PC | | Original | | | |
| Oil Tycoon 2 | PC | | Original | | | |
| Oil Tycoon 2 Oil Tycoon 2: Il Ritorno di una Leggenda | PC | | EXA Games | | EXAG020 | |
| Oil Tycoon 2 | PC | | Covermount | | | |
| OIO: The Game: Enlarged | PC | | F*ckn' Best of Independent Games: Collection Vol. 1 | | | |
| Oksfordzka Encyklopedia Historii Świata | PC | | Covermount | | SELL 0103 | |
| Oksfordzka Encyklopedia Historii Świata. Tom II | PC | | Covermount | | SELL 0108 | |
| Old El Paso Recipes for Family Fun | PC | | Original | | | |
| Olimpiada Zimowa 2002 Olimpijskie Zmagania 2002 | PC | | Original | | | |
| Olivers Äventyr: Drakens Förbannelse | PC | | Original | | 021120110 | |
| Ollo en de Reuzentomaat | PC | | CD-ROM Topper | | | |
| Olympiad Qiaosai 2 奧林匹亞橋賽2 | PC | | Original | | | |
| Olympic Games: Atlanta 1996 | PC | | Original | | | |
| Olympic Soccer | PC | | Kixx | | | |
| Omar Sharif on Bridge | PC | | Valueware | | CD-ICD-148-0 | |
| Omerta: City of Gangsters | PC | | Covermount | | G1DVD0215 | |
| Omikron: The Nomad Soul | PC | | Promo | | | |
| Omnia Junior 1: Enciclopedia: Dizionario | PC | | Covermount | | SIAE 08A01PA | |
| Omnia Junior 2: Storia: Attività interattive | PC | | Covermount | | SIAE 0901PA | |
| Omnia Junior 3: Il Mondo degli Animali | PC | | Covermount | | SIAE1001PA | |
| On Air | PC | | Original | | BROWNIE 990201 | |
| Ona: Sbornik e'roticheskix igr Она: Сборник эротических игр | PC | | Original | | 10-20999 | |
| One Must Fall 2097 One Must Fall | PC | | Rerelease | | D.L.: M-8684-97 | |
| One Must Fall 2097 | PC | | Original | | EPOMF01 | |
| One Two Animal: Let's Animal Series 1 ワンツーあにまる レッツあにまるシリーズ1 | PC | | Original | | LAOA-96101 | |
| Onegai Countdown おねがいカウントダウン | PC | | Original | | YMH-0013 | |
| Oni / 4x4 Evo Oni / 4x4 Evolution | PC | | Demo | | 12DC1-09GM03-11 | |
| Onible'jd Ониблэйд | PC | | Original | | | |
| Onigunsou Kuramochi Yuzo no Yatchimasu: Spartan Manshu 鬼軍曹倉持勇造の殺っちます ~スパルタン満州~ | PC | | Original | | | |
| Onikiri-den 鬼斬伝 | PC | | Original | | ZEUS-00001 | |
| Onimusha: Put' samuraja Onimusha: Путь самурая | PC | | Original | | | |
| Onimusha: Put' samuraya (Disc 1) (Igrovoj) Onimusha: Путь самурая | PC | | Original | | | |
| Onimusha: Put' samuraya (Disc 2) Onimusha: Путь самурая | PC | | Original | | | |
| Onimusha: Put' samuraya (Disc 3) Onimusha: Путь самурая | PC | | Original | | | |
| Onimusha: Put' samuraya (Disc 4) Onimusha: Путь самурая | PC | | Original | | | |
| Onkel Alberts geheimnisvolles Notizbuch | PC | | Original | | | |
| Online G@mer n. 5: Juin/Juillet 2001 (Disc 1) | PC | | | | | |
| OnlineGamez | PC | | | | | |
| Only Fun: Entra anche tu nel mondo dei Videogames | PC | | | | | |
| 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 | |
| Onsalakorv | PC | | Original | | | |
| Onsen de Takkyuu 温泉de卓球 | PC | | Original | | | |
| Oozora ni Kodawarou! Minna no Kuukou 2 大空にこだわろう! みんなの空港2 | PC | | | | | |
| Open Kart | PC | | I Videogiochi del "Giornalino" | | | |
| Open Season (Disc 1) | PC | | Original | | 5004905-CD 1 | |
| Open Season (Disc 2) | PC | | Original | | 5004905-CD 2 | |
| Open Season (Disc 3) | PC | | Original | | 5004905-CD 3 | |
| Opera Fatal | PC | | Tandem | | 1444 | |
| Opera Fatal | PC | | Original | | | |
| Opera House Preview Disc オペラハウス プレビューディスク | PC | | Original | | | |
| Opera House Preview Disc #2 オペラハウス プレビューディスク #2 | PC | | Original | | | |
| Opera House Preview Disc #2.3 オペラハウス プレビューディスク #2.3 | PC | | Original | | | |
| Operaciya "Barbarossa" Операция "Барбаросса" | PC | | Original | | | |
| Operaciya "Blau" Операция "Блау" | PC | | Original | | | |
| Operaciya "Plastilin" (Disc 1) Операция "Пластилин" | PC | | Original | | | |
| Operaciya "Plastilin" (Disc 2) Операция "Пластилин" | PC | | Original | | | |
| Operaciya Silent Storm: Chasovye (Disc 1) Операция Silent Storm: Часовые | PC | | 1С: Igroteka | | | |
| Operaciya Silent Storm: Chasovye (Disc 2) Операция Silent Storm: Часовые | PC | | 1С: Igroteka | | | |
| Operation | PC | | General Mills | | AM801R5 | |
| Operation Barbarossa: The Struggle for Russia | PC | | Original | | | |
| Operation Body Count: One Level Preview | PC | | Original | | | |
| Operation Flashpoint: Cold War Crisis | PC | | Playable Demo | | POPFCDUS40 | |
| Operation Flashpoint: Dragon Rising | PC | | Original | | MOFP2CDEU00 | |
| Operation Flashpoint: Gold Upgrade Operace Flashpoint: Gold Upgrade | PC | | Original | | | |
| Operation: Surgery Has Never Been so Silly! | PC | | Replay Kids | | OPERPCREGB/A | |
| Operation: Surgery Has Never Been so Silly! | PC | | Sold Out Software | | | |
| The Operational Art of War II: 1956-2000 The Operational Art of War II: Bewaffnete Konflikten | PC | | Original | | | |
| The Operational Art of War: Century of Warfare | PC | | 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 2) (In the Lounge with No One Lives Forever) | PC | | Bundle Version Micro-Star International OEM | | CD-W581995-MSYZ2 | |
| Opowieści z Narnii: Książe Kaspian | PC | | Covermount | | | |
| Opsys | PC | | Original | | | |
| Optimum Resource Sampler | PC | | Rerelease | | | |
| Optimum Resource Sampler | PC | | Original | | | |
| The Orange Box (Disc 1) | PC | | Original | | VAX07705811D | |
| The Orange Box (Disc 1) | PC | | Original | | VAD07705811D | |
| The Orange Box (Disc 2) | PC | | Original | | VAD07705811D2 | |
| The Orange Box (Disc 1) | PC | | Original | | VAI07705811D | |
| The Orange Box (Disc 2) | PC | | Original | | VAI07705811D2 | |
| The Orange Box (Disc 1) | PC | | Rerelease | | | |
| The Orange Box (Disc 1) | PC | | Rerelease | | | |
| The Orange Box (Disc 1) | PC | | Original | | | |
| The Orange Box (Disc 2) | PC | | Rerelease | | | |
| The Orange Box (Disc 2) | PC | | Rerelease | | | |
| The Orange Box (Disc 2) | PC | | Original | | | |
| 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 | |
| Orda: Severnyj veter Орда: Северный ветер | PC | | Original | | | |
| Order of War: Osvobozhdenie Order of War: Освобождение | PC | | Igromaniya: Vybor redakcii | | | |
| Order of War: Stolknovenie Order of War: Столкновение | PC | | Igromaniya: Vybor redakcii | | | |
| 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: Classic Edition | PC | | SoftKey | | POT144EE-CD | |
| The Oregon Trail: Classic Edition | PC | | SoftKey | | POT144BE-CD | |
| Orgaslave (Side-1) オルガスレイブ | PC | | Original | | H PT 003-1 | |
| Orgaslave (Side-2) オルガスレイブ | PC | | Original | | H PT 003-2 | |
| Orgazumi (Disc 1) オーガズミー | PC | | Original | | FCG013 | |
| Orgazumi (Disc 2) オーガズミー | PC | | Original | | FCG014 | |
| Die Original Moorhuhn Jagd | PC | | Best of Moorhuhn | | | |
| The Original Mulan 花木兰 | PC | | Original | | | |
| Orion Burger | PC | | Original | | | |
| Orion Burger | PC | | Gold Games 2 (CD 11) | | SPI 046 | |
| Orion Burger | PC | | Abenteuer Doppelpack: Premier Collection | | MOBRLPGE72 | |
| Orly's Draw-A-Story | PC | | Original | | | |
| Oro e Gloria: La Strada per El Dorado | PC | | Covermount | | | |
| Oro Negro: Juego de Guerra y Estrategia | PC | | Covermount | | | |
| Ortofrajda | PC | | | | | |
| Osaka Ennichi 大阪緣日 | PC | | Original | | OE-V1.00 | |
| Osananajimi wa Pet Yakuza! 幼なじみはペットヤクザ!体験版 | PC | | Taikenban | | | |
| Oscar | PC | | Golden Zone | | | |
| Oscar der Ballonfahrer und die Geheimnisse des Waldes | PC | | | | | |
| Osef Minei Mischakim אוסף מיני משחקים | PC | | Original | | | |
| Osobennosti nacional'nogo razvoda (Disc 1) Особенности национального развода | PC | | Original | | | |
| Osobennosti nacional'nogo razvoda (Disc 2) Особенности национального развода | PC | | Original | | | |
| Ost-Indskaya kompaniya: Zolotoe izdanie Ост-Индская компания: Золотое издание | PC | | Original | | | |
| Osterspiele-Box Oster Spielebox | PC | | Original | | | |
| Ostrich Runner | PC | | Microforum | | | |
| Ostrov e'rotiki Остров эротики | PC | | Original | | | |
| Ot zakata do rassveta От заката до рассвета | PC | | 1C: Igroteka | | | |
| Otchayannye domoxozyajki (Disc 1) (Ustanovochnyj disk) Отчаянные домохозяйки | PC | | Original | | | |
| Otchayannye domoxozyajki (Disc 2) (Ustanovochnyj disk) Отчаянные домохозяйки | PC | | Original | | | |
| Otchayannye domoxozyajki (Disc 3) (Igrovoj disk) Отчаянные домохозяйки | PC | | Original | | | |
| Othelanian Wars オセラニアン・ウォーズ | PC | | Original | | | |
| Othello | PC | | Original | | | |
| Othello CD-ROM | PC | | Original | | | |
| Otorva v shkole Оторва в школе | PC | | Original | | | |
| Otousan no Tame no Hanafuda Tenkomori お父さんのための花札 てんこもり | PC | | Original | | THT-063 | |
| 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 | |
| Otverzhennye: Tajna temnoj rasy (Disc 1) Отверженные: Тайна темной расы | PC | | 1C: Igrushki | | SNOW OT21 0110 IR | |
| Otverzhennye: Tajna temnoj rasy (Disc 2) Отверженные: Тайна темной расы | PC | | 1C: Igrushki | | SNOW OT21 0110 IR | |
| Oudou Yuusha 王道勇者 | PC | | Original | | ALS-0029 | |
| Oujisama Lv1 王子さまLv1 | PC | | Original | | | |
| Ouro e Glória: O Caminho para El Dorado | PC | | Original | | 906.02.0 | |
| Outbreaker | PC | | Original | | | |
| Outburst | PC | | Classic Value Series | | Product# 99043 | |
| Outcast | PC | | Original | | | |
| Outcast (Disc 1) | PC | | Original | | OUTCAPC52F/A1 | |
| Outcast (Disc 2) | PC | | Limitierte Sonderausgabe | | OUTCAPC520/A2 | |
| Outcast (Disc 1) | PC | | Covermount | | | |
| Outcast (Disc 2) | PC | | Covermount | | | |
| Outlast: A Reading for Information Game | PC | | Original | | HH824 | |
| Outlaw Racers | PC | | Sold Out Software | | | |
| Outlaws (Disc 1) | PC | | Original | | | |
| Outlaws (Disc 1) | PC | | M6 Multimedia | | M6IMM6 | |
| Outlaws (Disc 2) | PC | | Original | | | |
| Outlaws (Disc 2) | PC | | M6 Multimedia | | M6IMM6 | |
| Outpost | PC | | Original | | S390021012ZZ2 | |
| Outpost | PC | | SierraOriginals | | S4941220Z12Z2 | |
| Outpost | PC | | Original | | S 390121012ZZZ | |
| Outpost | PC | | Original | | S725430 | |
| Outrage | PC | | Original | | | |
| OutRun 2006: Coast 2 Coast | PC | | eXtra Klasyka XK HIT | | TS OCC PL | |
| OutRun 2006: Coast 2 Coast | PC | | Top Games | | SEGA-PC029 | |
| Outward | PC | | Day One Edition | | 1024669LAINT, 103699 | |
| Over 1000 Games: The Complete Encyclopedia of Games: Volume II (Disc 1) Over 1000 Games Volume 2 | PC | | Original | | | |
| Over 1000 Games: The Complete Encyclopedia of Games: Volume II (Disc 2) Over 1000 Games Volume 2 | PC | | Original | | | |
| Over 200 Programs for Windows STG Computers LTD Windows Extra CD-ROM | PC | | Original | | | |
| Over 350 Jigsaw Puzzles | PC | | Original | | 012163 | |
| Over 350 Solitaire Games | PC | | Original | | | |
| Over Load | PC | | | | | |
| Overboard! | PC | | Original | | | |
| Overboard! | PC | | Dice | | DCG 005752, DMM 005776 | |
| Overboard! | PC | | Dice | | DCG 005752, DMM 005776 | |
| Overlord | PC | | Original | | MOVL1CDEU00 | |
| Overlord BGamer 153 (Side A) | PC | | Covermount | | | |
| Overlord II | PC | | Preview Code | | | |
| Overwatch | PC | | Game of the Year Edition, Legendary Edition | | 73052010US, S7302210 | |
| Overwatch | PC | | Origins Edition | | | |
| The Oxfordshire Golf Club | PC | | Original | | EAE05101006D | |
| Oynayarak Ogreniyorum 1 Oynayarak Öğreniyorum 1 | PC | | Original | | | |
| Oyungezer: Mart 2010 | PC | | | | | |
| Oyunlarla Dil Bilgisi Oyunlarla Matematik | PC | | Original | | | |
| Oz: The Magical Adventure | PC | | Original | | | |
| Ozzie's World オジィーズワールド | PC | | Original | | ASOW-71110 | |
| Ozzie's World | PC | | Original | | | |
| Owlboy (Game Disc) | PC | 0.0.6152.604 | IndieBox | | | |
| Orly Pervoj mirovoj Орлы Первой мировой | PC | 02.19.07 | Original | | | |
| The Oregon Trail 4th Edition (Disc 1) | PC | 1 | Original | | OTF744AE-CD1 | |
| The Oregon Trail 4th Edition (Disc 2) | PC | 1 | Rerelease | | OTF744CE-CD2 | |
| The Oregon Trail 4th Edition (Disc 2) | PC | 1 | Original | | OTF744AE-CD2 | |
| The Oregon Trail 4th Edition (Disc 3) | PC | 1 | Original | | OTF744AE-CD3 | |
| Oblivious Garden: Carmina Burana (Disc 1) (Game Disk) | PC | 1.0 | Standard Edition | | | |
| ObsCure (Disc 1) 惊悚空间 | PC | 1.0 | Original | | | |
| ObsCure (Disc 2) 惊悚空间 | PC | 1.0 | Original | | | |
| ObsCure (Disc 3) 惊悚空间 | PC | 1.0 | Original | | | |
| ObsCure (Disc 4) 惊悚空间 | PC | 1.0 | Original | | | |
| ObsCure (Disc 1) | PC | 1.0 | Original | | PCO457CD | |
| ObsCure (Disc 2) | PC | 1.0 | Original | | PCO457CD | |
| ObsCure (Disc 3) | PC | 1.0 | Original | | PCO457CD | |
| ObsCure (Disc 4) | PC | 1.0 | Original | | PCO457CD | |
| ObsCure (Disc 5) | PC | 1.0 | Original | | PCO457CD | |
| ObsCure II | PC | 1.0 | Covermount | | | |
| Obsidian (Disc 1) オブシディアン | PC | 1.0 | Original | | INR-1003 | |
| Obsidian (Disc 2) オブシディアン | PC | 1.0 | Original | | INR-1003 | |
| Obsidian (Disc 3) オブシディアン | PC | 1.0 | Original | | INR-1003 | |
| Obsidian (Disc 4) オブシディアン | PC | 1.0 | Original | | INR-1003 | |
| Obsidian (Disc 5) オブシディアン | PC | 1.0 | Original | | INR-1003 | |
| Obsidian | PC | 1.0 | Demo | | | |
| Oda Nobunaga Den 織田信長伝 | PC | 1.0 | Original | | KN11-93101 | |
| Oddballz: Your Wacky Computer Petz | PC | 1.0 | Original | | CS090370 | |
| Oddworld: Abe's Exoddus (Disc 1) | PC | 1.0 | Covermount | | | |
| Oddworld: Abe's Exoddus (Disc 2) | PC | 1.0 | Covermount | | | |
| Oil Tycoon | PC | 1.0 | Original | | | |
| Oktoberfest Wiesn-Gaudi | PC | 1.0 | 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 | | | |
| OMSI Add-on: Wien: Der Hochflurbus LU 200 | PC | 1.0 | OMSI Bundle | | | |
| On the Ball: League Edition | PC | 1.0 | Original | | | |
| Oni | PC | 1.0 | Covermount | | | |
| Oni | PC | 1.0 | Covermount | | | |
| Open Season Boog & Elliot | PC | 1.0 | Demo | | | |
| Opening Night | PC | 1.0 | Original | | #HCD646A | |
| Opening Night: Behind The Scenes | PC | 1.0 | Original | | #HCD646B | |
| Operation Flashpoint: Cold War Crisis | PC | 1.0 | Original, Gold Edition | | MOPFCDEU00 | |
| Operation Thunderstorm | PC | 1.0 | Original | | | |
| 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 2) | PC | 1.0 | Original | | FXX08903223D2 | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.0 | Original | | | |
| The Operative: No One Lives Forever (Disc 2) | PC | 1.0 | Original | | | |
| The Oregon Trail 3rd Edition: Pioneer Adventures | PC | 1.0 | DVD-ROM | | ORG811AE-DVD | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.0 | Original | | OTA744AE-CD1 | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.0 | Scholastic | | 380859-CD WP2 | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.0 | Original | | 380859A-CD | |
| Oregon Trail II | PC | 1.0 | Original | | | |
| Outlaws (Disc 1) | PC | 1.0 | Original | | | |
| Outlaws (Disc 2) | PC | 1.0 | Original | | | |
| Outpost 2: Destini Sospesi | PC | 1.0 | Covermount | | | |
| Outpost 2: Geteilte Bestimmung | PC | 1.0 | Original | | S0011248 | |
| OutRun 2006: Coast 2 Coast | PC | 1.0 | Original | | SEGA-PC029 | |
| Outwars (Disc 1) | PC | 1.0 | Original | | 0398 Artikelnr. X00-14039 DE | |
| Outwars (Disc 2) | PC | 1.0 | Original | | 0398 Artikelnr. X00-14040 DE | |
| Ovech'i bega Овечьи бега | PC | 1.0 | Original | | | |
| Outlaws (Disc 1) | PC | 1.0 Build 3 | Original | | 9511830 | |
| Outlaws (Disc 1) | PC | 1.0 Build 3 | Bundle Version Diamond OEM | | 644430 | |
| Outlaws (Disc 2) | PC | 1.0 Build 3 | Original | | 9511831 | |
| Outlaws (Disc 2) | PC | 1.0 Build 3 | Bundle Version Diamond OEM | | 644431 | |
| ObsCure II | PC | 1.0.0.0 | Original | | | |
| The Outforce | PC | 1.0.0.0 | Original | | | |
| 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 | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.0.0.4 | Game of the Year Edition (Covermount) | | | |
| Oni no Kamen 鬼ノ仮面 | PC | 1.00 | Original | | | |
| Onsen Ryokou Kakumei: Ich liebe dich.! 温泉旅行革命 ~Ich liebe dich.!~ | PC | 1.00 | Original | | RUCCA-003 | |
| 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 | | | |
| Oni | PC | 1.00.000 | Original | | MTW-0390 | |
| OutRun 2006: Coast 2 Coast | PC | 1.00.0000 | Serie Maxima II | | SEGA-PC029 | |
| Ostrov Nanda Остров Нанда | PC | 1.000 | Original | | | |
| 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 | 1.004 | Game of the Year Edition (BestSeller Series) | | JCPL11, S0026695 | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.004 | Game of the Year Edition | | S0025036 | |
| 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 | | | |
| 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 | |
| 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 2) ノーワンリブスフォーエバー | PC | 1.004, 1.004J | Original | | | |
| Oil Tycoon | PC | 1.01 | Original | | | |
| The Orion Conspiracy | PC | 1.01 | Original | | | |
| Outlive | PC | 1.01 | Original | | | |
| The Operational Art of War II | PC | 1.01.02 | Xplosiv | | EI-1259-3 | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.01E | Enhanced Education Version | | 480599-CD | |
| Original War (Disc 1) | PC | 1.02 | Covermount | | | |
| Original War (Disc 1) | PC | 1.02 | Original | | CD-W95-V006-IT1 | |
| Original War (Disc 2) | PC | 1.02 | Covermount | | | |
| Original War (Disc 2) | PC | 1.02 | Original | | CD-W95-V006-IT2 | |
| O.R.B.: Orbital'nye Resursnye Bazy О.Р.Б.: Орбитальные Ресурсные Базы | PC | 1.03 | 1C: Kollekciya igrushek | | | |
| OMSI: Der Omnibussimulator | PC | 1.04 | OMSI Bundle | | | |
| Obitel' t'my: Sumerki Обитель тьмы: Сумерки | PC | 1.1 | Original | | | |
| ObsCure | PC | 1.1 | Covermount | | | |
| The Oregon Trail 4th Edition (Disc 1) | PC | 1.1 | Rerelease | | OTF744BE-CD1 | |
| The Oregon Trail 4th Edition (Disc 2) | PC | 1.1 | Rerelease | | OTF744BE-CD2 | |
| The Oregon Trail 4th Edition (Disc 3) | PC | 1.1 | Rerelease | | OTF744BE-CD3 | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.1 | Rerelease, Southwestern School Set | | 380859B-CD | |
| The Oregon Trail | PC | 1.1 | Original | | #HCD606 | |
| Overclocked: Una Storia di Violenza | PC | 1.1 | Original | | | |
| On-Robot Он-Робот | PC | 1.14SB | 1C: Igrushki | | | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.2 | Rerelease | | OTA744BE-CD1 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 2) | PC | 1.2 | Original | | OTA744BE-CD2 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | 1.2 | Original | | OTA744BE-CD3 | |
| The Oregon Trail | PC | 1.2 | Original | | #HCD706 | |
| The Oregon Trail | PC | 1.2 | Original | | #HCD706 | |
| Overlord | PC | 1.2 | Original | | | |
| Outpost 2: Divided Destiny | PC | 1.2.0.5 | Original | | | |
| Oudou Aniki 王道兄貴 | PC | 1.20b | Original | | | |
| Operation Neptune | PC | 1.22 | Original | | ONT744CE-CD | |
| The Oregon Trail | PC | 1.22 | Smart Saver | | ORT844AE-CD | |
| Operation Neptune | PC | 1.23 | The ClueFinders: Math Ages 9-12 | | ONT744EE-CD | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.2a | Bundle Version Compaq Presario OEM | | | |
| Oregon Trail II | PC | 1.3 | Smart Saver | | 0TT744AE-CD | |
| Oregon Trail II | PC | 1.3 | Smart Saver | | 381032-CD/i401ha | |
| Oregon Trail II: 25th Anniversary Limited Edition | PC | 1.3 | Original, SoftKey | | #OTR744AE-CD | |
| Overlord: Raising Hell | PC | 1.3 | Original | | | |
| Operation Flashpoint: Gold Upgrade | PC | 1.30 | Original, Gold Edition | | MOFUCDEU00, MOFUCDUS00 | |
| Oregon Trail II | PC | 1.31 | Rerelease | | HCD744BE-CD | |
| Oregon Trail II | PC | 1.31 | Rerelease | | #HCD744AE-CD | |
| Oregon Trail II | PC | 1.32 | Rerelease | | #HCD744CE-CD | |
| Obduction | PC | 1.4.2 | Kickstarter | | | |
| Operation Flashpoint: Holodnaja vojna Операция Flashpoint: Холодная война | PC | 1.46 | Original | | | |
| Outpost | PC | 1.51 | Schweinepreise | | S390122CZ12ZZ | |
| Oni 奥妮 | PC | 1.7 | Original | | | |
| Operation Flashpoint: Resistance | PC | 1.75 | Original | | MOFRCDEU00 | |
| Operation Flashpoint: Resistance | PC | 1.75 | Original | | MOFRCDUS00 | |
| Odysseia ΟΔΥΣΣΕΙΑ | PC | 1.8 | Original | | | |
| Operation Flashpoint: Soprotivlenie Operation Flashpoint: Сопротивление | PC | 1.85 | | | | |
| Oddworld: Abe's Exoddus (Play Disc) | PC | 2.0 | Budget, Covermount | | MMICDR 5280 | |
| Oddworld: Abe's Exoddus (Install) | PC | 2.0 | Original | | 04-15993CD1 | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Covermount | | IB2G-ODDI5 | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Channelware | | 04-15303 | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Original | | 04-12608CD | |
| Outlaws (Disc 1) | PC | 2.0 | Collection LucasArts | | | |
| Outlaws (Disc 2) | PC | 2.0 | Collection LucasArts | | | |
| Outlaws (Disc 1) | PC | 2.0 | Rerelease | | 9511830 | |
| Outlaws (Disc 1) | PC | 2.0 | Rerelease | | 9511830 | |
| Outlaws (Disc 2) | PC | 2.0 | Rerelease | | 9511831 | |
| Outlaws (Disc 2) | PC | 2.0 | Rerelease | | 9511831 | |
| Outlaws: Cidade Sem Lei (Disc 1) | PC | 2.0 | Original | | 0806.05.0 | |
| Ougon Musou Kyoku Cross 黄金夢想曲 CROSS | PC | 2.00 | Original | | | |
| Oscar Wilde's The Selfish Giant | PC | 2.10 | Original | | MQ 13-004-144 | |
| The Oregon Trail: Classic Edition | PC | 3.0.1 | SoftKey | | POT144CE-CD | |
| ODS Robot Challenge | PC | 5.0.1r26 | Teacher's Edition | | | |
| Obitel' T'my Обитель Тьмы | PC | 5.02 04/07/03 | Original | | | |
| 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 | | | |
| Ori and the Blind Forest: Definitive Edition | PC | 5.3.2.9582331 | Limited Edition | | | |
| Operaciya Silent Storm (Disc 1) Операция Silent Storm | PC | Aug 11 2003 | 1C: Igroteka | | | |
| Operaciya Silent Storm (Disc 2) Операция Silent Storm | PC | Aug 11 2003 | 1C: Igroteka | | | |
| Outlaws (Demonstration Program) | PC | Demo 1.0 CD Build 3 | Demo | | 644230 | |
| Ore no Shita de Agake 俺の下であがけ | PC | System3.9 Ver.5.43 | Original | | ALB-005 | |
| Obratnyj otschet Обратный отсчет | PC | v.1 1.06.10.22 | Original | | | |
| Outcry (Disc 1) Outcry: The Dawn | PC | Version DPV 1.0 | Original | | PCO596CD | |
| Outcry (Disc 2) Outcry: The Dawn | PC | Version DPV 1.0 | Original | | PCO596CD | |