O'Riley's Mine Commodore C64
Obelix Atari 2600
Obliterate Playstation 2
Oblivion XBOX 360
Oblivion PC
Obscure XBOX
Obscure 2 Playstation 2
Obscure 2 PC
OC Racing Playstation 2
Ocean Commander Playstation 2
Ocean Trader DOS PC
Octoplex Commodore C64
Odama Game Cube
Oddworld XBOX
Oddworld Adventures GameBoy
Odin Sphere Playstation 2
Off Road Nintendo NES
Off the Wall Atari 2600
Off Your Rocker Atari 2600
Offroad Extreme Playstation 2
Ogre Battle Super Nintendo
Oh My God! Arcade
Oh No! Commodore C64
OHG Commodore C64
Oids Atari ST
Oil Imperium aka Black Gold DOS PC
Oils Well DOS PC
Oink! Atari 2600
Ojanko High School Arcade
Okami Playstation 2
Okuman Choja Game GameBoy Advance
Olli & Lissa Commodore C64
Olympic Gold Sega Master System
Olympic Summer Games Sega Mega Drive
Olympic Winter Games Sega Mega Drive
Omega Commodore C64
Omega Fighter Arcade
Omega Race Commodore C64
Omnibus GMBH Commodore C64
On the Ball DOS PC
One Man and His Droid Commodore C64
One Piece Wii
One Piece Grand Adventure Game Cube
One Piece Grand Battle Game Cube
One Piece Land Land Playstation 2
One Piece Pirates' Carnival Game Cube
One-on-One Basketball Atari 7800
Onimusha Playstation 2
Onimusha 3 PC
Onimusha Blade Warriors Playstation 2
Online Chess Kingdoms Sony PSP
Onna Sansirou Arcade
Open Ice 2-on-2 Challenge Arcade
Open Season PC
Open Season Playstation 2
Open Season Wii
Open Season XBOX 360
Operation Air Assault Playstation 2
Operation Europe DOS PC
Operation Fireball Commodore C64
Operation Fox Commodore C64
Operation Hanoi Commodore C64
Operation Neptune Commodore C64
Operation Thunderbolt Arcade
Operation Wolf Sega Master System
Operation Wolf Nintendo NES
Operation Wolf! Commodore C64
Orange Honey Playstation 2
Orbitron Arcade
Ordyne PC Engine
Origamo DOS PC
Oscar DOS PC
Oscar's Trash Race Atari 2600
Oskar Commodore Amiga
Osprey! Commodore C64
Othello Nintendo NES
Othello Atari 2600
Othello Milaniam GameBoy Color
Otogi 2 XBOX
Otsomatsu-kun Hachamecha Gekiio Sega Mega Drive
Otto's Ottifanten GameBoy
Our Breeding Series GameBoy Advance
Out of This World Super Nintendo
Out Run Sega Mega Drive
Out Run 2019 Sega Mega Drive
Out Runners Sega Mega Drive
Out to Lunch Super Nintendo
Outcast PC
Outlander Super Nintendo
Outlanders Nintendo NES
Outlaw Atari 2600
Outlaw Golf 2 XBOX
Outlaw Tennis XBOX
Outlaw Volleyball XBOX
Outlaws PC
Outline Arcade
Outrun Sega Master System
Outrun Commodore C64
OutRun 2006 Playstation 2
OutRun 2006 Coast 2 Coast Sony PSP
Outrun Europa Sega Master System
Over G Fighters XBOX 360
Over Lord Nintendo NES
Over the Hedge Playstation 2
Over the Hedge Sony PSP
Over the Hedge Nintendo DS
Overclocked PC
Overlander Commodore C64
Overlander Commodore Amiga
Overlord PC
Overrun Europe Commodore C64
Oystron Atari 2600
Ozma Wars Arcade

Obelix GameBoy Color
Obitus DOS PC
Oblivion PC
Oblivion Playstation 3
Obscure PC
Obscure Playstation 2
Obscure 2 Wii
OC Racing XBOX
Ocean City Defender Atari 2600
Ocean Ranger DOS PC
Octapolis Commodore C64
Octopus Atari 2600
Oddworld XBOX
Oddworld Abe's Oddysee PC
Odentodo DOS PC
OEL Commodore C64
Off Road Arcade
Off The Wall Arcade
Offensive DOS PC
Ogre Commodore C64
Ogre Battle Playstation
Oh no DOS PC
Ohasta Yamachan & Reimondo GameBoy Color
Ohgon no Siro Arcade
Oil Imperium Commodore C64
Oilmania Commodore C64
Oils Well Commodore C64
Oira Jajamaru Sekaidai Boken GameBoy
Ojanko Yakata Arcade
Okie Dokie Atari 2600
Oli-Boo-Chu Arcade
Ollie's Follies Commodore C64
Olympic Gold Sega Mega Drive
Olympic Summer Games GameBoy
Olympics Spectacular Commodore C64
Omega Arcade
Omega Race Sega Mega Drive
Omega Race Atari 2600
On Court Tennis Commodore C64
On the Tiles GameBoy Color
One on One Commodore C64
One Piece Grand Adventure Playstation 2
One Piece Grand Battle Playstation 2
One Piece Grand Battle 3 Playstation 2
One Piece Pirates Carnival Playstation 2
One Step Beyond DOS PC
Oni PC
Onimusha 2 Playstation 2
Onimusha 3 Playstation 2
Onimusha Warlords Playstation 2
Online Pro Wrestling Playstation 2
Onslaught Sega Mega Drive
Open Kart PC
Open Season XBOX
Open Season Game Cube
Open Season Sony PSP
Open Sesame Atari 2600
Operation Darkness XBOX 360
Operation Europe Sega Mega Drive
Operation Flashpoint XBOX
Operation Frog DOS PC
Operation Hormuz Atari ST
Operation Thunderbolt Commodore C64
Operation Winback Playstation 2
Operation Wolf PC Engine
Operation Wolf Arcade
Operators Side Voice Action Adventure Playstation 2
Orb 3-D Nintendo NES
Orbs of Doom Playstation 2
Ordyne Arcade
Orion Commodore C64
Oscar Amiga CD32
Oskar Commodore C64
Osomatsu-Kun Nintendo NES
Ostfrieslandgames Commodore C64
Othello Commodore C64
Othello Derby Arcade
Otogi XBOX
Otona no Mahjong Arcade
Otto Show Commodore C64
Our Breeding Series GameBoy Advance
Out Live PC Engine
Out Of This World Commodore Amiga
Out Run Arcade
Out Run Europa Commodore C64
Out Runners Arcade
Out Zone Arcade
Outer Ridge DOS PC
Outlander Sega Mega Drive
Outlaw Commodore C64
Outlaw Golf Game Cube
Outlaw Golf 2 Playstation 2
Outlaw Tennis Playstation 2
Outlaw Volleyball Remixed Playstation 2
Outlaws Commodore C64
OutRun DOS PC
OutRun PC Engine
OutRun 2 Playstation 2
OutRun 2006 Coast 2 Coast XBOX
Outrun 3D Sega Master System
OutRun2 XBOX
Over Horizon Nintendo NES
Over the Hedge XBOX
Over the Hedge Game Cube
Over the Hedge Nintendo DS
Over the Net Commodore C64
Overkill Amiga CD32
Overlander Atari ST
Overlord XBOX 360
Override PC Engine
Overtop Neo Geo
Oz Playstation 2