Left 4 Dead Bundle include 2 items:Left 4 Dead and Left 4 Dead 2.
Left 4 Dead:
From Valve comes Left 4 Dead, a co-op action horror game for the PC and Xbox 360 that casts up to four players in an epic struggle for survival against swarming zombie hordes and terrifying mutant monsters.
Set in the immediate aftermath of the zombie apocalypse, L4D's survival co-op mode lets you blast a path through the infected in four unique “movies,” guiding your survivors across the rooftops of an abandoned metropolis, through rural ghost towns and pitch-black forests in your quest to escape a devastated Ground Zero crawling with infected enemies. Each "movie" is comprised of five large maps, and can be played by one to four human players, with an emphasis on team-based strategy and objectives.
Left 4 Dead 2:
Set in the zombie apocalypse, Left 4 Dead 2 is the highly anticipated sequel to the award-winning Left 4 Dead.
This co-operative action horror FPS takes you and your friends through the cities, swamps and cemeteries of the Deep South, from Savannah to New Orleans across five expansive campaigns.
You'll play as one of four new survivors armed with a wide and devastating array of classic and upgraded weapons. In addition to firearms, you'll also get a chance to take out some aggression on infected with a variety of carnage-creating melee weapons, from chainsaws to axes and even the deadly frying pan.