Dota 2 is an action strategy title for the PC and Mac. It is being developed by Valve Corporation, and is the stand-alone sequel to a popular mod created for WarCraft III, called Defence of the Ancients (Dota), which is itself loosely based on a custom map for the original StarCraft, called Aeon of Strife.

Left 4 dead is a first person shooter game, with one simple objective, survive! You and 3 others (ai or human) must fight the undead while trying to escape, make it to the safe house and youve fought to live another day. die and you join the undead and there relentless quest for brains!

Half-Life 2 is a shooter game developed by Valve Corporation and released on Mac OS, Microsoft Windows, PlayStation 3, Xbox.