| Game Name | System |
|---|
| OPTION Tuning Car Battle Spec-R (Japan) | PSX |
| OSCOM Nano | MAME |
| OVL '96 (UK) (1998) (PD) | CPC |
| OVL '96 Tools To Copy Disk (UK) (1998) (PD) | CPC |
| OVL '96 Tools To Copy Disk (UK) (1998) (PD) [a1] | CPC |
| OVR Compil Code (19xx)(OVR) | Atari ST |
| Oasis Backgammon (19xx)(-) | ZX Spectrum Z80 |
| Oasis Backgammon (19xx)(-)[a] | ZX Spectrum Z80 |
| Oath, The | Amiga |
| Oba-Oba (set 1) | MAME |
| Oba-Oba (set 2) | MAME |
| Obake no Q Tarou - Wanwan Panic (Japan) | NES |
| Obelix (1983) (Atari, Andrew Fuchs, Jeffrey Gusman, Dave Jolly, Suki Lee) (CX26117) | 2600 |
| Oben (Germany) | PSP |
| Oberon 69 | Amiga |
| Oberon 69 (1990)(Diabolic Software)(Sp) | ZX Spectrum Z80 |
| Oberon 69 (1990)(Diabolic Software)(Sp)[a] | ZX Spectrum Z80 |
| Obitus | Amiga |
| Obitus (1991)(Psygnosis) | DOS |
| Obitus (1991)(Psygnosis)(Disk 1 of 2)[cr ICS][m EMT][t][b] | Atari ST |
| Obitus (1991)(Psygnosis)(Disk 1 of 3)[cr Elite] | Atari ST |
| Obitus (1991)(Psygnosis)(Disk 2 of 2)[cr ICS][m EMT][t][b] | Atari ST |
| Obitus (1991)(Psygnosis)(Disk 2 of 3)[cr Elite] | Atari ST |
| Obitus (1991)(Psygnosis)(Disk 3 of 3)[cr Elite] | Atari ST |
| Obitus (USA) | SNES |
| Objective Kursk (1984)(SSI) | Apple2 |
| Obliterate (Europe) | PS2 |
| Obliterator | Amiga |
| Obliterator (1988)(Avalon Interactive) | DOS |
| Obliterator (1988)(Psygnosis)(Disk 1 of 2) | Atari ST |
| Obliterator (1988)(Psygnosis)(Disk 2 of 2) | Atari ST |
| Obliterator (1988)(Psygnosis)[cr Was -Not Was-][one disk] | Atari ST |
| Obliterator (1989)(Melbourne House) | ZX Spectrum Z80 |
| Obliterator (1989)(Melbourne House)(128k) | ZX Spectrum Z80 |
| Obliterator (1989)(Melbourne House)(128k)[a] | ZX Spectrum Z80 |
| Obliterator (1989)(Melbourne House)[a2] | ZX Spectrum Z80 |
| Obliterator (1989)(Melbourne House)[a] | ZX Spectrum Z80 |
| Obliterator (UK) (1988) | CPC |
| Obliterator (UK) (1988) [a1] | CPC |
| Obliterator (UK) (1988) [a2] | CPC |
| Obliterator (UK) (1988) [a3] | CPC |
| Obliterator (UK) (1988) [t1] | CPC |
| Obliterator (UK) (1988) [t2] | CPC |
| Oblitroid | Atari 800 |
| Oblivion (1983)(Bug Byte)[OBLIVIO start] [SSD] | BBC Micro |
| Oblivion (1983)(Bug Byte)[a][OBLIVIO start] [SSD] | BBC Micro |
| Oblivion (1983)(Bug Byte)[h TSTH][bootfile] [SSD] | BBC Micro |
| Oblivion (19xx)(Alpha Omega Software) | ZX Spectrum Z80 |
| Obocchama Kun (Japan) | NES |
| Obocchama Kun (Japan) | TG16 |
| Obronca_Ziemi | Atari 800 |
| Obs Prog (19xx)(-) | ZX Spectrum Z80 |
| Obs Prog (19xx)(-)[a] | ZX Spectrum Z80 |
| ObsCure (Europe) | PS2 |
| ObsCure (Europe) (De,Es) | PS2 |
| ObsCure II (Europe) (En,Fr,De,Es,It) | PS2 |
| Obscure - The Aftermath (USA) (En,Fr,Es) | PS2 |
| Obscure The Aftermath (Europe) | PSP |
| Obscure The Aftermath (USA) | PSP |
| Observational_Astronomy_Program | Atari 800 |
| Obsession | Amiga |
| Obsession (1994)(Unique Development Sweden)(Disk 1 of 2) | Atari ST |
| Obsession (1994)(Unique Development Sweden)(Disk 1 of 2)[cr Euroswap] | Atari ST |
| Obsession (1994)(Unique Development Sweden)(Disk 1 of 2)[cr Vectronix] | Atari ST |
| Obsession (1994)(Unique Development Sweden)(Disk 1 of 2)[cr Vectronix][a] | Atari ST |
| Obsession (1994)(Unique Development Sweden)(Disk 2 of 2) | Atari ST |
| Obsession (1994)(Unique Development Sweden)(Disk 2 of 2)[cr Euroswap] | Atari ST |
| Obsession (1994)(Unique Development Sweden)(Disk 2 of 2)[cr Vectronix] | Atari ST |
| Obsession (1994)(Unique Development Sweden)(Disk 2 of 2)[cr Vectronix][a] | Atari ST |
| Obsidian (UK) (1985) | CPC |
| Obstickle | Amiga |
| Obunsha Deru-jun - Koumin DS (J)(6rz) | NDS |
| Obunsha Deru-jun - Sansuu DS (J)(6rz) | NDS |
| Obunsha Deru-jun Chiri DS (J)(Independent) | NDS |
| Obunsha Deru-jun Kokugo DS (J)(Independent) | NDS |
| Ocean Beach Volley (1989)(Ocean)(Disk 1 of 2) | Atari ST |
| Ocean Beach Volley (1989)(Ocean)(Disk 1 of 2)[a] | Atari ST |
| Ocean Beach Volley (1989)(Ocean)(Disk 2 of 2) | Atari ST |
| Ocean Beach Volley (1989)(Ocean)(Disk 2 of 2)[a] | Atari ST |
| Ocean Beach Volley (1989)(Ocean)[cr MCA][splitted Version] | Atari ST |
| Ocean Beach Volley (1989)(Ocean)[cr Manolo le Gitan][t] | Atari ST |
| Ocean Beach Volley (1989)(Ocean)[cr Manolo le Gitan][t][a] | Atari ST |
| Ocean Compilation (UK) (Green Beret & Rambo & Top Gun & Amcharge) | CPC |
| Ocean Conqueror (1987)(Rack It) | ZX Spectrum Z80 |
| Ocean Conqueror (1987)(Rack It)[a] | ZX Spectrum Z80 |
| Ocean Conqueror (1987)(Rack-It) | ZX Spectrum (TAP) |
| Ocean Conqueror (UK) (19xx) | CPC |
| Ocean Conqueror (UK) (19xx) [a1] | CPC |
| Ocean Dancer (19xx)(C. Woodhouse) | ZX Spectrum Z80 |
| Ocean Dynamite Compilation (UK) (Disk 1 of 4) | CPC |
| Ocean Dynamite Compilation (UK) (Disk 2 of 4) | CPC |
| Ocean Dynamite Compilation (UK) (Disk 3 of 4) | CPC |
| Ocean Dynamite Compilation (UK) (Disk 4 of 4) | CPC |
| Ocean Ranger (UE) | C64 PP |
| Ocean Trader (1995)(Software 2000) | DOS |
| Ocean to Ocean (Medal) (DECO Cassette MD) (No.10/Ver.1,Japan) | MAME |
| Ocean to Ocean (Medal) (DECO Cassette MD) (No.10/Ver.6,US) | MAME |
| Ocean's All Star Hits 2 (Army Moves & Cobra & Head Over Heels) | CPC |
| Ocean's All Star Hits 2 (Mutants & Wizball & Tank) | CPC |
| Ocean-240 Test Rom | MAME |
