 The popularity of the game led to the development of a sequel, "Left 4 Dead 2", which was released on November 17, 2009.A new map for both "Left 4 Dead" and "Left 4 Dead 2", called "The Sacrifice", was released on October 5, 2010.In July 2012, all "Left 4 Dead" campaigns were ported over to "Left 4 Dead 2", with cross-platform multiplayer support between Windows and Mac versions of the game.