| Titre | Année | Genre |
|---|---|---|
| Octagon Reversi | 2000 | Réflexion |
| Oh! Hajiki! | ???? | Réflexion |
| Oh! Hajiki! Final | 1990 | Réflexion |
| Oh! Pai | ???? | Réflexion |
| Ohootsuku Ni Kiyu | ???? | Aventures |
| Okumanchouja | ???? | Aventures |
| Olteus II | 1991 | Shoot em up |
| One-key Flying | ???? | Shoot em up |
| Oni Gokko 68 | ???? | Aventures |
| Ooedo Hanseiki | ???? | Réflexion |
| Ora Ora Ball | 1995 | Arcade |
| Ora-Shoot | 1996 | Shoot em up |
| Orange Iro No Biyaku | 1989 | Réflexion |
| Ossan No Dotsuki Game Special | ???? | Arcade |
| Othello Master | 1991 | Réflexion |
| Otoko Dama | 1999 | Shoot em up |
| Otoshite Pon | ???? | Réflexion |
| Otsukerumono No Tetsujin | 1996 | Shoot em up |
| Ouen no Uta | 2000 | Aventures |
| Ougon No Buta | ???? | Arcade |
| Over Driver | 1992 | Shoot em up |
| Overtake | ???? | Formule 1 |
