Portal (2007), Buka Entertainment
Half-Life 2: Episode One (2006), Valve Corporation
Left 4 Dead 2 (2009), Valve Corporation
Quake (1998), Midway Games, Inc.
Quake III: Arena (2000), SEGA Corporation
Final DOOM (1996), Atari, Inc.
Half-Life 2: Episode Two (2007), Buka Entertainment
The Orange Box (2007), Valve Corporation
Left 4 Dead (2008), Valve Corporation
DOOM 64 (1997), Midway Games, Inc.
Return to Castle Wolfenstein: Operation Resurrection (2003), Activision Publishing, Inc.
Counter-Strike: Source (2004), Valve Corporation
Half-Life 2 (2004), Valve Corporation
DOOM (1995), Williams Entertainment Inc.
Quake II (1999), Activision, Inc.
DOOM (1996), Art Data Interactive, Inc.

Half-Life 2: Episode Two (2007), Buka Entertainment
Final DOOM (1996), Atari, Inc.
Quake III: Arena (2000), SEGA Corporation
Left 4 Dead 2 (2009), Valve Corporation
Quake (1998), Midway Games, Inc.
Half-Life 2: Episode One (2006), Valve Corporation
The Orange Box (2007), Valve Corporation
Left 4 Dead (2008), Valve Corporation
Quake II (1999), Activision, Inc.
DOOM (1995), Williams Entertainment Inc.
Half-Life 2 (2004), Valve Corporation
Counter-Strike: Source (2004), Valve Corporation
Return to Castle Wolfenstein: Operation Resurrection (2003), Activision Publishing, Inc.
DOOM 64 (1997), Midway Games, Inc.
DOOM (1996), Art Data Interactive, Inc.

Half-Life 2 (2004), Valve Corporation
Quake II (1999), Activision, Inc.
DOOM (1996), Art Data Interactive, Inc.
Half-Life 2: Episode One (2006), Valve Corporation
Quake III: Arena (2000), SEGA Corporation
Final DOOM (1996), Atari, Inc.
Half-Life 2: Episode Two (2007), Buka Entertainment

Half-Life 2 (2004), Valve Corporation
The Orange Box (2007), Valve Corporation
Portal (2007), Buka Entertainment

DOOM (1996), Art Data Interactive, Inc.
DOOM (1995), Williams Entertainment Inc.

Half-Life 2: Episode Two (2007), Buka Entertainment
Half-Life 2: Episode One (2006), Valve Corporation

Left 4 Dead (2008), Valve Corporation
Left 4 Dead 2 (2009), Valve Corporation