| Title | Year | Genre |
|---|---|---|
| Oboro Muramasa | 2009 | Action |
| Obscure - The Aftermath | 2008 | Adventure |
| Obscure 2 | 2008 | Adventure |
| Ocean Commander | 2009 | Shooter |
| Octomania | 2008 | Puzzle |
| Off Road | 2008 | Racing |
| Offroad Extreme! | 2008 | Racing |
| Offroad Extreme! Special Edition | 2007 | Racing |
| Offshore Tycoon | 2009 | Arcade |
| Okami | 2008 | Adventure |
| Once Upon A Time | 2010 | Educational |
| One Piece - Unlimited Adventure | 2007 | Action |
| One Piece Unlimited Cruise 1 - The Treasure Beneath the Waves | 2009 | Adventure |
| One Piece Unlimited Cruise 2 - Awakening of a Hero | 2009 | Action |
| Onechanbara - Bikini Zombie Slayers | 2009 | Action |
| Onechanbara Revolution | 2008 | Action |
| Oops! Prank Party | 2010 | Arcade |
| Open Season | 2006 | Adventure |
| Opoona | 2008 | RPG |
| Order Up! | 2008 | Arcade |
| Oregon Trail, The | 2011 | Adventure |
| Osouji Sentai Clean Keeper | 2008 | Adventure |
| Ougon no Kizuna | 2009 | Adventure |
| Our House Party | 2009 | Arcade |
| Outdoor Action Double Pack | 2010 | Compilation |
| Overlord - Dark Legend | 2009 | Adventure |
| Oyako de Asobo - Miffy no Omocha Bako | 2010 | Educational |
