Region | Title | System | Version | Edition | Languages | Serial | Status |
| Obsidian (Disc 1) | MAC | | Original, Great Series | | INR-001, MKM-001 | |
| Obsidian (Disc 2) | MAC | | Original, Great Series | | INR-001, MKM-001 | |
| Obsidian (Disc 3) | MAC | | Original, Great Series | | INR-001, MKM-001 | |
| Obsidian (Disc 4) | MAC | | Original, Great Series | | INR-001, MKM-001 | |
| Obsidian (Disc 5) | MAC | | Original, Great Series | | INR-001, MKM-001 | |
| Oceans Below The Software Toolworks Presents ... Oceans Below | MAC | | Original | | 2198620-590001 / I 073100, CDRM1103420 | |
| Oddworld: Abe's Exoddus: UK Packaging | MAC | | Art Assets | | | |
| Online Start-Up Disc v1.0 Disco de Inicio en Línea v1.0 | PS2 | 1.00 | Original | | PBPX 95250 … | |
| Ontdek de Interactieve Wereld van Neckermann | CDI | | Original | | | |
| Oogst van de Zon | CDI | | Original | | 814 0004 | |
| Oregon Trail II | PC | 1.31 | Rerelease | | HCD744BE-CD | |
| Othello | CDI | | Original | | 810 0163 | |
| Oni 奥妮 | PC | 1.7 | Original | | | |
| Ontdek het Onbekende Nederland | CDI | 1.06 | Original | | 814 0104 | |
| Op Jacht naar Vernuft | CDI | | | | | |
| Origami | CDI | | Original | | 810 0041 | |
| Othello | PC | | Original | | | |
| 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 | |
| O.D.T. | PSX | | Original | | SLES-01391 | |
| O.D.T. | PSX | | Original | | SLUS-00698 | |
| O.D.T. | PSX | | Demo | | SLUS-90043 | |
| Obliterate | PS2 | 1.01 | Original | | SLES-53355 … | |
| 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, Complimentary Copy | | 11008 | |
| Oceans Below | 3DO | | Original | | | |
| Oddballz: Your Wacky Computer Petz | PC | 1.0 | Original | | CS090370 | |
| 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) | PSX | | Original, Platinum | | SLES-01480 … | |
| Oddworld: Abe's Exoddus (Disc 2) | PSX | | Original, Platinum | | SLES-11480 … | |
| Oddworld: Abe's Exoddus (Play) | PC | | Original | | 04-15993CD2 | |
| Oddworld: Abe's Exoddus (Install) | PC | 2.0 | Original | | 04-15993CD1 | |
| Oddworld: Abe's Exoddus (Disc 1) | PSX | | Original | | SLUS-00710 … | |
| Oddworld: Abe's Exoddus (Disc 2) | PSX | | Original | | SLUS-00731 … | |
| Oddworld: Abe's Exoddus + Duke Nukem: Time To Kill + B-Movie | PSX | | Demo | | SLED-01608 | |
| Oddworld: Abe's Oddysee | PSX | | Demo | | SLED-00725 | |
| Oddworld: Abe's Oddysee | PSX | | Original, Platinum, Best of Infogrames: Value Series, Best of Infogrames: Adventure | | SLES-00664 … | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Original | | IB2G-ODD5 | |
| Oddworld: Abe's Oddysee | PSX | | Original | | SLUS-00190 | |
| Oddworld: Abe's Oddysee | PSX | | Demo | | SLUS-90004 | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Original | | 04-12608CD | |
| Oddworld: Abe's Oddysee | PSX | Rev 1 | Original, Greatest Hits | | SLUS-00190 | |
| Oddworld: Abe's Oddysee | PSX | Rev 2 | Greatest Hits | | SLUS-00190 | |
| Odell Down Under | PC | | Original, SoftKey | | POD544AE-CD | |
| Odium ōdi·um | PC | | Original | | CD-W58-1104-0 | |
| 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 | |
| Off-World Interceptor | 3DO | | Original | | | |
| Off-World Interceptor Extreme | PSX | | Original | | SLES-00047 | |
| Off-World Interceptor Extreme | PSX | | Original | | SLUS-00020 | |
| The Official Guide to Babylon 5 The Official Guide to J. Michael Straczynski's Babylon 5 | PC | | Original | | | |
| Official PlayStation Magazine Best Games Ever 2000 | PSX | | | | SCED-03375 | |
| Official PlayStation Magazine Platinum Special Demo Official UK PlayStation Magazine Platinum Special | PSX | | | | SCED-02122 | |
| Official Sega Dreamcast Magazine: Special Edition Preview PC CD-ROM | PC | | | | | |
| Official U.S. PlayStation Magazine Demo Disc 01 | PSX | | | | SCUS-94189 | |
| Official U.S. PlayStation Magazine Demo Disc 02 | PSX | | | | SCUS-94198 | |
| Official U.S. PlayStation Magazine Demo Disc 03 | PSX | | | | SCUS-94210 | |
| Official U.S. PlayStation Magazine Demo Disc 04 | PSX | | | | SCUS-94211 | |
| Official U.S. PlayStation Magazine Demo Disc 05 | PSX | | | | SCUS-94212 | |
| Official U.S. PlayStation Magazine Demo Disc 06 | PSX | | | | SCUS-94213 | |
| Official U.S. PlayStation Magazine Demo Disc 07 | PSX | | | | SCUS-94214 | |
| Official U.S. PlayStation Magazine Demo Disc 08 | PSX | | | | SCUS-94215 | |
| Official U.S. PlayStation Magazine Demo Disc 09 | PSX | | | | SCUS-94216 | |
| Official U.S. PlayStation Magazine Demo Disc 10 | PSX | | | | SCUS-94217 | |
| Official U.S. PlayStation Magazine Demo Disc 11 | PSX | | | | SCUS-94218 | |
| Official U.S. PlayStation Magazine Demo Disc 12 | PSX | | | | SCUS-94219 | |
| Official U.S. PlayStation Magazine Demo Disc 13 | PSX | | | | SCUS-94275 | |
| Official U.S. PlayStation Magazine Demo Disc 14 | PSX | | | | SCUS-94276 | |
| Official U.S. PlayStation Magazine Demo Disc 15 | PSX | | | | SCUS-94277 | |
| Official U.S. PlayStation Magazine Demo Disc 16 | PSX | | | | SCUS-94278 | |
| Official U.S. PlayStation Magazine Demo Disc 17 | PSX | | | | SCUS-94279 | |
| Official U.S. PlayStation Magazine Demo Disc 18 | PSX | | | | SCUS-94280 | |
| Official U.S. PlayStation Magazine Demo Disc 19 | PSX | | | | SCUS-94281 | |
| Official U.S. PlayStation Magazine Demo Disc 20 | PSX | | | | SCUS-94282 | |
| Official U.S. PlayStation Magazine Demo Disc 21 | PSX | | | | SCUS-94429 | |
| Official U.S. PlayStation Magazine Demo Disc 22 | PSX | | | | SCUS-94430 | |
| Official U.S. PlayStation Magazine Demo Disc 23 | PSX | | | | SCUS-94431 | |
| Official U.S. PlayStation Magazine Demo Disc 24 | PSX | | | | SCUS-94432 | |
| Official U.S. PlayStation Magazine Demo Disc 25 | PSX | | | | SCUS-94433 | |
| Official U.S. PlayStation Magazine Demo Disc 26 | PSX | | | | SCUS-94434 | |
| Official U.S. PlayStation Magazine Demo Disc 27 | PSX | | | | SCUS-94435 | |
| Official U.S. PlayStation Magazine Demo Disc 28 | PSX | | | | SCUS-94436 | |
| Official U.S. PlayStation Magazine Demo Disc 29 | PSX | | | | SCUS-94437 | |
| Official U.S. PlayStation Magazine Demo Disc 30 | PSX | | | | SCUS-94438 | |
| Official U.S. PlayStation Magazine Demo Disc 31 | PSX | | | | SCUS-94499 | |
| Official U.S. PlayStation Magazine Demo Disc 32 | PSX | | | | SCUS-94583 | |
| Official U.S. PlayStation Magazine Demo Disc 33 | PSX | | | | SCUS-94591 | |
| Official U.S. PlayStation Magazine Demo Disc 34 | PSX | | | | SCUS-94593 | |
| Official U.S. PlayStation Magazine Demo Disc 35 | PSX | | | | SCUS-94596 | |
| Official U.S. PlayStation Magazine Demo Disc 36 | PSX | | | | SCUS-94599 | |
| Official U.S. PlayStation Magazine Demo Disc 37 | PSX | | | | SCUS-94614 | |
| Official U.S. PlayStation Magazine Demo Disc 38 | PSX | | | | SCUS-94617 | |
| Official U.S. PlayStation Magazine Demo Disc 39 | PSX | | | | SCUS-94622 | |
| Official U.S. PlayStation Magazine Demo Disc 40 | PSX | | | | SCUS-94628 | |
| Official U.S. PlayStation Magazine Demo Disc 41 | PSX | | | | SCUS-94630 | |
| Official U.S. PlayStation Magazine Demo Disc 42 | PSX | | | | SCUS-94631 | |
| Official U.S. PlayStation Magazine Demo Disc 43 | PSX | | | | SCUS-94634 | |
| Official U.S. PlayStation Magazine Demo Disc 43 | PSX | EDC | | | SCUS-94634 | |
| Official U.S. PlayStation Magazine Demo Disc 44 | PSX | | | | SCUS-94637 | |
| Official U.S. PlayStation Magazine Demo Disc 45 | PSX | | | | SCUS-94645 | |
| Official U.S. PlayStation Magazine Demo Disc 46 | PSX | | | | SCUS-94649 | |
| Official U.S. PlayStation Magazine Demo Disc 47 | PSX | | | | SCUS-94652 | |
| Official U.S. PlayStation Magazine Demo Disc 48 | PSX | | | | SCUS-94655 | |
| Official U.S. PlayStation Magazine Demo Disc 50 | PSX | | | | SCUS-94658 | |
| Official U.S. PlayStation Magazine Demo Disc 52 | PSX | | | | SCUS-94662 | |
| Official U.S. PlayStation Magazine Demo Disc 54 | PSX | | | | SCUS-94664 | |
| Ogre Battle: Limited Edition | PSX | | Original | | SLUS-00467 | |
| Oh Yes... More Worms! Volume 1 | ACD | | Original | | | |
| Ohio Distinctive Software Vol. I | PC | | | | | |
| Öhlins Hyper-Rally ハイパーラリー | PSX | | Original | | SLPS 00462 | |
| Oil Tycoon | PC | 1.01 | Original | | | |
| Okage: Shadow King | PS2 | 1.01 | Original | | SCUS 97129 | |
| Olympic Games | 3DO | | Bundled with Magazine (Demo) | | | |
| Olympic Soccer | PSX | | Original | | SLUS-00156 | |
| Olympic Summer Games | PSX | | Original | | SLUS-00148 | |
| Olympic Summer Games | 3DO | | Original | | FZ-SW0012 | |
| Omar Sharif Bridge | PC | 1.0 | Original | | | |
| Omega Boost | PSX | | Original | | SCUS-94449 | |
| 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 | PSX | | Demo | | SLED-01170 | |
| One | PSX | | Original | | SLUS-00469 | |
| One Piece Mansion | PSX | | Original | | SLES-03723 | |
| One Piece Mansion | PSX | | Original | | SLUS-01406 | |
| One Unit Whole Blood | PC | 1.21 | Original | | 04-16459CD1 | |
| Oni | PS2 | 1.02 | Original, Platinum | | SLES-50134 … | |
| Oni | PC | 1.0 | Original | | | |
| Oni | PS2 | 1.20 | Original | | SLUS-20064 | |
| Online Start-Up Disc 4.0 | PS2 | 1.00 | | | SCUS-97357 | |
| Online Start-Up Disc 4.0: Broadband Only | PS2 | 1.02 | Bundled with PS2 | | PBPX 95248 … | |
| Online Start-Up Disc v3.0 | PS2 | 1.01 | | | PBPX-95242 | |
| Online Start-Up Disc v3.0 | PS2 | 1.01 | | | SCUS 97425 | |
| Online Start-Up Disc v3.5: Broadband Only | PS2 | 1.00 | Original | | PBPX 95247 | |
| OnSide Soccer | 3DO | | Unlicensed (oldergames, Good Deal Games Double Header! Two Game Set) | | | |
| Operation | PC | | General Mills | | AM801R5 | |
| Operation Air Assault | PS2 | 1.01 | Original | | SLES-52572 | |
| Operation Air Assault 2 | PS2 | 1.01 | Original | | SLES-54804 | |
| Operation Flashpoint: Cold War Crisis | PC | 1.0 | Original | | MOPFCDUS00 | |
| Operation Flashpoint: Gold Upgrade | PC | 1.30 | Original | | MOFUCDUS00 | |
| Operation Flashpoint: Resistance | PC | 1.75 | Original | | MOFRCDUS00 | |
| 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 | 1.0.0.4 | 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) | | JCPL11, S0026179, S0026696 | |
| OPSM Best PS One Games Ever Official Australian PlayStation Magazine Demo 44 | PSX | | | | SCED-03239 | |
| 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 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 | 1.0 | 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 | |
| Oretachi Geesen Zoku: Super Volleyball オレたちゲーセン族 スーパーバレーボール | PS2 | 1.04 | Original | | SLPM 62660 | |
| The Original Links | PC | | Solid Gold Edition | | | |
| Oscar | PC | | Original | | | |
| Oscar | PC | | Jackson Libri | | | |
| Out of This World | 3DO | | Original | | | |
| Out of This World | 3DO | RE | 3DO Maniac Pack | | | |
| 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 (Disc 1) | PC | 1.0 Build 3 | Original | | 9511830 | |
| Outlaws (Disc 1) | PC | 1.0 Build 3 | Bundle Version Diamond OEM | | 644430 | |
| 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 | | | |
| 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 | | | |
| Over Drivin' DX: Rally Edition オーバードライビンDX ラリーエディション | PSX | | Hibaihin | | SLPM 80032 | |
| OverBlood | PSX | | Original | | SLES-00768 | |
| OverBlood | PSX | | Original | | SLUS-00464 | |
| OverBlood 2 (Disc 1) | PSX | Rev 1 | Original | | SLES-01879 … | |
| OverBlood 2 (Disc 2) | PSX | Rev 1 | Original | | SLES-11879 … | |
| Overboard! | PC | | Original | | | |
| Overboard! | PC | | Dice | | DCG 005752, DMM 005776 | |
| Overboard! | PSX | | Original, 1998 4 PlayStation Multi Pack | | SLES-00865 | |
| Overkill & Lunar-C | CD32 | | Original | | /DP130002 | |
| Oddworld: Abe's Exoddus + Duke Nukem: Time to Kill + Duke Nukem: 3D | PSX | | | | SLED-01655 | |
| Orion's Puzzle Collection | DC | 1.000 | Unlicensed | | | |
| Operation WinBack | PS2 | 1.10 | Original | | SLES-50155 | |
| Official Formula 1 Racing | PC | | Original | | | |
| Official PlayStation 2 Magazine Demo 1 | PS2 | 1.00 | | | SCED-50065 | |
| Official PlayStation 2 Magazine Demo 2 | PS2 | 1.00 | | | SCED-50066 | |
| Official PlayStation 2 Magazine Demo 3 | PS2 | 1.00 | | | SCED-50067 | |
| Official PlayStation 2 Magazine Demo 5 | PS2 | 1.00 | | | SCED-50140 | |
| Olympic Games Olympic Games: Atlanta 1996 | PSX | | Original | | SLES-00110 | |
| Olympic Soccer | PSX | | Original | | SLES-00113 | |
| Olympic Soccer | SS | 2.000 | Original | | T-7904H-09, T-7904H-50 | |
| Olympic Soccer | 3DO | | Original | | FZ-SW0011 | |
| Omega Boost | PSX | | Original | | SCES-02120 | |
| Omikron: The Nomad Soul | DC | 1.001 | Original | | T-36807N | |
| One | PSX | | Original | | SLES-00944 | |
| Operation Flashpoint: Cold War Crisis | PC | 1.0 | Original, Gold Edition | | MOPFCDEU00 | |
| Operation Flashpoint: Cold War Crisis | PC | | The Games Collection | | | |
| Operation Flashpoint: Gold Upgrade | PC | 1.30 | Original, Gold Edition | | MOFUCDEU00, MOFUCDUS00 | |
| Operation Flashpoint: Resistance | PC | 1.75 | Original | | MOFRCDEU00 | |
| Oracle no Houseki: Jewels of the Oracle オラクルの宝石 | SS | 1.004 | Original | | T-1511G | |
| Onside Complete Soccer | PSX | | Original | | SLES-00079 | |
| Onside Complete Soccer | PSX | Rev 1 | Original | | SLES-00079 | |
| 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 | |
| Omega Boost オメガ・ブースト | PSX | | Original, Preview | | SCPS 10020 | |
| Oshidashi Zintrick ~ ZinTricK 押し出しジントリック | NGCD | | Original | | ADCD-104 | |
| Otostaz オトスタツ | PS2 | 1.00 | Original | | SCPS 11024 | |
| O.D.T. | PSX | | Original | | SLES-01409 | |
| Oddworld: L'Exode d'Abe (Disc 1) | PSX | | Original | | SLES-01502 | |
| Oddworld: L'Exode d'Abe (Disc 2) | PSX | | Original | | SLES-11502 | |
| Oddworld: L'Odyssée d'Abe | PSX | | Original, Best of Infogrames | | SLES-00838 … | |
| L'Open de Palm Springs | CDI | | Original, For Demonstration Only | | 812 0002 | |
| Outlaws (Disc 1) | PC | | M6 Multimedia | | M6IMM6 | |
| Outlaws (Disc 2) | PC | | M6 Multimedia | | M6IMM6 | |
| O.D.T. | 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 | | | |
| Oddworld: Abe's Exoddus (Disc 1) | PSX | | Original | | SLES-01503 | |
| Oddworld: Abe's Exoddus (Disc 2) | PSX | | Original | | SLES-11503 | |
| Oddworld: Abe's Oddysee | PSX | | Platinum | | SLES-00839 | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Original | | IB2G-ODDG5 | |
| Oldtimer | ACD | | Original | | | |
| Oni | PS2 | 1.02 | Original | | SLES-50177 | |
| Die Original Moorhuhn Jagd | PC | | Best of Moorhuhn | | | |
| Orion Burger | PC | | Gold Games 2 (CD 11) | | SPI 046 | |
| Outpost 2: Geteilte Bestimmung | PC | 1.0 | Original | | S0011248 | |
| OverBlood | PSX | | Original | | SLES-00770 | |
| OverBlood 2 (Disc 1) | PSX | Rev 1 | Original | | SLES-02187 … | |
| OnEscapee | ACD | | Original | | | |
| O.D.T. | PSX | | Original | | SLES-01411 | |
| 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 (Disc 1) | PSX | | Original, Platinum | | SLES-01504 … | |
| Oddworld: Abe's Exoddus (Disc 2) | PSX | | Original, Platinum | | SLES-11504 … | |
| Oddworld: Abe's Oddysee | PSX | | Original | | SLES-00840 | |
| Oni | PS2 | 1.02 | Original | | SLES-50178 | |
| Open Kart | PC | | I Videogiochi del "Giornalino" | | | |
| Oro e Gloria: La Strada per El Dorado | PSX | | Original | | SLES-03186 | |
| Outcast (Disc 1) | PC | | Covermount | | | |
| Outcast (Disc 2) | PC | | Covermount | | | |
| 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 | |
| OverBlood 2 (Disc 1) | PSX | | Original | | SLES-01880 | |
| OverBlood 2 (Disc 2) | PSX | | Original | | SLES-11880 | |
| Ochigee Designer Tsukutte Pon! 落ちゲー・デザイナー 作ってポン! | SS | 1.090 | Original | | T-9108G | |
| Oda Nobunaga Den 織田信長伝 | PSX | | Original, Koei the Best | | SLPM 86337 … | |
| Odo Odo Oddity おどおどおっでぃ | PSX | | Original | | SLPS 00754 | |
| Official Fan Book: Circadia: Special CD-ROM オフィシャルファンブック サーカディア | PSX | | Original | | SCZS 94106 | |
| Official Yarudora Fan Book: Double Cast: CD-ROM Special Data-shuu オフィシャルやるドラファンブック ダブルキャスト | PSX | | Original | | SCZS 94101 | |
| Official Yarudora Fan Book: Kisetsu o Dakishimete オフィシャルやるドラファンブック 季節を抱きしめて | PSX | | Original | | SCZS 94102 | |
| Official Yarudora Fan Book: Sampaguita オフィシャルやるドラファンブック サンパギータ | PSX | | Original | | SCZS 94103 | |
| Official Yarudora Fan Book: Yukiwari no Hana: CD-ROM Special Data-shuu オフィシャルやるドラファンブック 雪割りの花 | PSX | | Original | | SCZS 94104 | |
| Oh-chan no Oekaki Logic おーちゃんのお絵かきロジック | PSX | | Original, SunColle Best, Value 1500 | | SLPS 00093 … | |
| Oh-chan no Oekaki Logic おーちゃんのお絵かきロジック | SS | 1.005 | Original | | T-1508G | |
| Oh-chan no Oekaki Logic 2 おーちゃんのお絵かきロジック2 | PSX | Rev 1 | SunColle Best, Value 1500 | | SLPS 02145 … | |
| Ojousama Express (Disc 1) お嬢様特急 | PSX | | Original | | SLPS 01495 | |
| Ojousama Express (Disc 1) お嬢様特急 | SS | 1.005 | Original | | T-27803G | |
| Ojousama Express (Disc 2) お嬢様特急 | PSX | | Original | | SLPS 01496 | |
| Ojousama Express (Disc 2) お嬢様特急 | SS | 1.005 | Original | | T-27803G | |
| Ojousama o Nerae!! お嬢様を狙え!! | SS | 1.002 | Original | | T-38101G | |
| Ojousama Sousamou お嬢様捜査網 | PC-FX | | Original | | FXNHE616 | |
| Okappari-ou 陸釣王 | PSX | | Original | | SLPS 01524 | |
| Olympia, Takasago: Virtua Pachi-Slot III オリンピア・高砂 バーチャ・パチスロⅢ | PSX | | Original | | SLPS 01386 | |
| Omakase! Savers おまかせ!退魔業 | SS | 1.002 | Original | | GS-9030 | |
| Omega Boost オメガ・ブースト | PSX | | Taikenban | | PAPX 90080 | |
| One ワン | PSX | | Original | | SLPS 01812 | |
| One Piece Mansion ワンピースマンション | PSX | | Taikenban | | SLPM 80617 | |
| One Piece Mansion ワンピースマンション | PSX | | Original | | SLPM 86837 | |
| Onee-san to Issho! Kisekae Paradise お姉さんといっしょ! 着せ替え パラダイス | 3DO | | Original | | FZ-SJ5252 | |
| Ongaku Tkool: Kanadeeru 2 音楽ツクール かなで~る2 | PSX | | Original | | SLPS 00903 | |
| Online Games: Dai Guru Guru Onsen オンラインゲームズ 大ぐるぐる温泉 | PS2 | 1.01 | Original | | SLPM 62195 | |
| Ooedo Fuusui Ingaritsu: Hanabi 2 大江戸風水因果律 花火2 | PSX | | Original | | SLPS 02814 | |
| Ooedo Renaissance 大江戸ルネッサンス | SS | 1.001 | Original | | T-9104G | |
| Ookami-teki Monshou: Crest of Wolf 狼的紋章 クレスト・オブ・ウルフ | PCE | | Original | | HCD3044 | |
| The Open Golf: History of Turnberry ジ・オープンゴルフ History of Turnberry | PSX | | Original | | SLPS 00418 | |
| 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 | | | |
| Option: Tuning Car Battle オプション チューニングカーバトル | PSX | | Original | | SLPS 01207 | |
| Option: Tuning Car Battle 2 オプション チューニングカーバトル2 | PSX | | Original | | SLPS 01857 | |
| Option: Tuning Car Battle Spec R オプション チューニングカーバトル スペックR | PSX | | Original | | SLPS 02587 | |
| Orange Pocket: Cornet オレンジポケット -コルネット- | DC | 1.004 | Original, Shokai Genteiban | | T-18707M, T-18708M | |
| Ore no Ryouri 俺の料理 | PSX | | Original, PlayStation the Best | | SCPS 10099 … | |
| Ore no Shikabane o Koete Yuke 俺の屍を越えてゆけ | PSX | | Original, PlayStation the Best, PSone Books, PSone Books (Silver Disc) | | SCPS 10074 … | |
| Ore! Tomba オレっ!トンバ | PSX | | Taikenban | | SLPM 80165 | |
| Ore! Tomba オレっ!トンバ | PSX | | Original | | SLPS 01144 | |
| Oretachi Geesen Zoku: Akumajou Dracula オレたちゲーセン族 悪魔城ドラキュラ | PS2 | 1.01 | Original | | SLPM 62729 | |
| Oretachi Geesen Zoku: Karate-dou オレたちゲーセン族 空手道 | PS2 | 1.01 | Original | | SLPM 62628 | |
| Oretachi Geesen Zoku: Nekketsu Kouha Kunio-kun オレたちゲーセン族 熱血硬派くにおくん | PS2 | 1.01 | Original | | SLPM 62706 | |
| Oretachi Geesen Zoku: Pooyan オレたちゲーセン族 プーヤン | PS2 | 1.01 | Original | | SLPM 62731 | |
| Oretachi Geesen Zoku: Time Pilot オレたちゲーセン族 タイムパイロット | PS2 | 1.01 | Original | | SLPM 62644 | |
| 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 | |
| Oshigoto-shiki Jinsei Game: Mezase Shokugyou King お仕事式人生ゲーム めざせ職業王 | PSX | | Original, The Best Takaramono | | SLPM 87316 … | |
| Othello World II: Yume to Michi e no Chousen オセロワールドII 夢と未知への挑戦 | PSX | | Original, Fukkokuban | | SLPS 00136 … | |
| Other Life Azure Dreams アザーライフ アザードリームス | PSX | | Original | | SLPM 86047 | |
| Oto to E no Deru Eigo Jisho No. 2: English in Dream 音と絵の出る英語辞書 No.2 「English in Dream」 | FMT | | Original | | HMB-129 | |
| Oto to E no Deru Eigo Jisho No. 3: Nandemo Illust Eigo Jiten 音と絵の出る英語辞書 No.3 「なんでもいらすとえいごじてん」 | FMT | | Original | | HMB-131 | |
| Oto to E no Deru Eigo Jisho No. 4: Nandemo Illust Eigo Jiten Part 2 音と絵の出る英語辞書 No.4 「なんでもいらすとえいごじてん Part 2」 | FMT | | Original | | HMB-170 | |
| Otogi Story: Tenshi no Shippo おとぎストーリー ~天使のしっぽ~ | PSX | | Original | | SLPS 03531 | |
| Otostaz オトスタツ | PS2 | 1.00 | Taikenban | | PAPX 90228 | |
| Otostaz オトスタツ | PS2 | 1.00 | Taikenban | | SCPS 11020 | |
| Oudou Yuusha 王道勇者 | PC | | Original | | ALS-0029 | |
| Ougon Kishi Garo 黄金騎士 牙狼 | PS2 | 1.01 | Original | | SLPS 20463 | |
| Oukoku no Grand Chef 王国のグランシェフ | 3DO | | Original | | FZ-SJ4252 | |
| Oukyuu no Hihou Tension 王宮の秘宝 テンション | PSX | | Original, VAP Best Thanks 1800 | | SLPS 00438 … | |
| Oumagatoki 逢魔が時 | PSX | | Original, PSone Books | | SLPS 03235 … | |
| Oumagatoki 逢魔が時 プレミアム"FAN"ディスク | PSX | | Premium Fan Disc | | SLPM 80623 | |
| Over Drivin' DX オーバードライビンDX | PSX | | Original | | SLPS 00327 | |
| OverBlood オーバーブラッド | PSX | | Original, PlayStation the Best | | SLPS 00392 … | |
| OverBlood 2 オーバーブラッド2 | PSX | | Special Movie-ban | | PAPX 90046 … | |
| OverBlood 2 (Disc 1) オーバーブラッド2 | PSX | | Original | | SLPS 01261 | |
| OverBlood 2 (Disc 2) オーバーブラッド2 | PSX | | Original | | SLPS 01262 | |
| Oyaji Hunter Mahjong おやじハンター・マージャン | 3DO | | Original, Sample | | IMP-SF0703 | |
| Oksfordzka Encyklopedia Historii Świata | PC | | Covermount | | SELL 0103 | |
| Ob"ekt 69: Kasablanka Объект 69: Касабланка | PC | | Original | | RUSSOBIT-M 2003/408 | |
| Ob"ekt 69: Mest' Krassera Объект 69: Месть Крассера | PC | | Original | | | |
| Oni Они | PC | 1.0 | | | | |
| Operation Flashpoint: Holodnaja vojna Операция Flashpoint: Холодная война | PC | 1.46 | Original | | | |
| Otorva v shkole Оторва в школе | PC | | Original | | | |
| Otverzhennye: Tajna temnoj rasy (Disc 1) Отверженные: Тайна темной расы | PC | | 1C: Igrushki | | SNOW OT21 0110 IR | |
| Oddworld: Abe's Oddysee | PSX | | Original | | SLES-00841 | |
| Oni | PS2 | 1.02 | Original | | SLES-50179 | |