| The Official Frogger | 1983 | a2600 |
| Oh Mummy Genesis | 2012 | genesis |
| Oh No! | 2000 | ps1 |
| Oheya o Kazarou - Koinu no Heya | 2008 | nds |
| Oigas | 1986 | arcade |
| Oil's Well | 1984 | col |
| Oink! | 1983 | a2600 |
| Ojarumaru - Gekkouchou Sanpo de Ojaru | 2003 | gba |
| Ojarumaru - Mangan Jinja no Ennichi de Ojaru! | 2000 | gbc |
| Okage - Shadow King | 2001 | ps2 |
| Okami HD | 2012 | ps3, ps4 |
| Oli-Boo-Chu | 1981 | arcade |
| Olivmandingo | 1982 | arcade |
| Olympia Rising | 2016 | wiiu |
| Omega | 1986 | arcade |
| Omega Boost | 1999 | ps1 |
| Omega Race | 1983 | a2600, col |
| On Dal Jang Goon | 1989 | genesis |
| One | 1997 | ps1 |
| One Piece - Kaizoku Musou 2 | 2013 | ps3 |
| One Piece - Pirate Warriors 2 | 2013 | ps3 |
| One Piece - Pirate Warriors 3 | 2015 | ps3, ps4, vita |
| One Piece - Pirates Carnival Doukonban) | 2005 | ps2 |
| One Piece - Round the Land! | 2004 | ps2 |
| One Piece - Unlimited Cruise SP2 | 2012 | 3ds |
| One Piece: Pirate Warriors 3 Deluxe Edition | 2017 | switch |
| OneChanbara Special | 2011 | psp |
| Onechanbara - Bikini Samurai Squad | 2009 | xbox360 |
| Onechanbara Origin | 2019 | ps4 |
| Onechanbara Z2: Chaos | 2014 | ps4 |
| Oneechanbara Z - Kagura with NoNoNo! | 2013 | ps3 |
| Oni | 2001 | ps2 |
| Onimusha | 2001 | ps2 |
| Onimusha - Dawn of Dreams | 2006 | ps2 |
| Onimusha 2 | 2002 | ps2 |
| Onimusha 2 - Samurai's Destiny | 2002 | ps2 |
| Onimusha 3 | 2004 | ps2 |
| Onimusha 3 - Demon Siege | 2004 | ps2 |
| Onmyou Taisenki - Byakko Enbu | 2005 | ps2 |
| Onmyou Taisenki - Hasha no In | 2005 | ps2 |
| Onslaught | 1991 | genesis |
| Onyanko Town | 1985 | nes |
| Ooedo Senryoubako | 2006 | psp |
| Oof McBrewster's Haunted House Adventure | 2020 | nes |
| Ookami | 2006 | ps2 |
| Ookami Kakushi | 2009 | psp |
| The Ooze | 1995 | genesis |
| Opa Opa | 1987 | arcade, sms |
| Open Sesame | 1983 | a2600 |
| Operation Thunderbolt | 1994 | snes |
| Operator's Side | 2003 | ps2 |
| Opossum a la Mode | 2024 | gb |
| Oraga Land Shusai - Best Farmer Shuukakusai | 1995 | snes |
| Ordyne | 1988 | arcade, pcengine |
| Orphen - Scion of Sorcery | 2000 | ps2 |
| Osawagase! Penguin Boy | 1990 | gb |
| Oscar | 1996 | snes |
| Oshare Princess | 2002 | gba |
| Osouji Sentai Clean Keeper H | 2009 | ps2 |
| Otoboke Ninja Colosseum | 1995 | snes |
| Otogi | 2004 | xbox |
| Otogi - Hyakki Toubatsu Emaki | 2004 | xbox |
| The Otterman Empire | 2020 | switch |
| Ottifanten Pinball | 2005 | gba |
| Oukyuu no Hihou Tension | 1996 | ps1 |
| Ousama Game | 1998 | saturn |
| Out of Gas | 1992 | gb |
| Out of This World | 1992 | 3do, genesis, snes |
| Out to Lunch | 1993 | snes |
| Outback Joey | 1993 | genesis |
| Outbreak | 2017 | xboxone |
| Outburst | 1993 | gb |
| Outer World | 1992 | snes |
| Outlander | 1993 | genesis, snes |
| Outlaw | 1979 | a2600 |
| Outlaw ~ Gunslinger | 1978 | a2600 |
| Outline | 1982 | arcade |
| OverBlood | 1996 | ps1 |
| OverBlood 2 | 1998 | ps1 |
| Owarai Yoiko no Geemumichi - Oyaji Sagashite 3 Choume | 1999 | gbc |
| Owlboy | 2018 | ps4, switch, xboxone |
| Oystron | 1997 | a2600 |
| P-Man | 1995 | snes |
| P.T. Barnum's Acrobats | 1982 | o2 |
| PD Ultraman Invader | 1995 | ps1 |
| PSIBO | 2016 | wiiu |
| PaTaank | 1994 | 3do |
| Pac & Pal | 1983 | arcade |
| Pac-Gal | 1981 | arcade |
| Pac-Man | 1982 | a2600, col |
| Pac-Man | 1982 | a2600, a5200, intv, nes |
| Pac-Man | 1990 | fds, gb, gg, nes |
| Pac-Man | 1988 | nes |
| Pac-Man | 1999 | ngpc |
| Pac-Man | 2007 | wii |
| Pac-Man | 1980 | arcade |
| Pac-Man & Chomp Chomp | 1983 | arcade |
| Pac-Man & Galaga Dimensions | 2011 | 3ds |
| Pac-Man - Championship Edition | 1984 | nes |
| Pac-Man - Championship Edition | 1988 | nes |