uiGallery

dates are from various sources, and may be wrong

1998
• 1998 nov 19
  Half-Life is released
  source: steam
1999
• 1999 nov 1
  Half-Life: Opposing Force is released
  source: steam
2000
• 2000 nov 1
  Counter-Strike and Ricochet are released
  source: steam
2001
• 2001 jun 1
  Half-Life: Blue Shift is released
  source: steam
2003
• 2003 may 1
  Day of Defeat is released
  source: steam
2004
• 2004 jun 1
  Half-Life: Source is released
  source: steam
• 2004 nov 1
  Counter-Strike: Source is released
  source: steam
• 2004 nov 16
  Half-Life 2 is released
  source: steam
2005
• 2005 may 13
  Day of Defeat: Source is released
  source: steam
2006
• 2006 jun 1
  Half-Life 2: Episode One is released
  source: steam
2007
• 2007 oct 10
  Half-Life 2: Episode Two, Portal and Team Fortress 2 are released as part of The Orange Box
  source: steam
2008
• 2008 nov 17
  Left 4 Dead is released
  source: steam
2009
• 2009 nov 17
  Left 4 Dead 2 is released
  source: steam
2011
• 2011 apr 19
  Portal 2 is released
  source: steam