The Left 4 Dead Bundle includes:

• Left 4 Dead
• Left 4 Dead 2

About Left 4 Dead

From Valve (the creators of Counter-Strike, Half-Life and more) 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. 

New technology dubbed "the AI Director" is used to generate a unique gameplay experience every time you play. The Director tailors the frequency and ferocity of the zombie attacks to your performance, putting you in the middle of a fast-paced, but not overwhelming, Hollywood horror movie. 

• Addictive single player, co-op, and multiplayer action gameplay from the makers of Counter-Strike and Half-Life 
• Versus Mode lets you compete four-on-four with friends, playing as a human trying to get rescued, or as a zombie boss monster that will stop at nothing to destroy them.
• See how long you and your friends can hold out against the infected horde in the new Survival Mode
• An advanced AI director dynamically creates intense and unique experiences every time the game is played 
• 20 maps, 10 weapons and unlimited possibilities in four sprawling "movies" 
• Matchmaking, stats, rankings, and awards system drive collaborative play 
• Designer's Commentary allows gamers to go "behind the scenes" of the game 
• Powered by Source and Steam

About Left 4 Dead 2

Set in the zombie apocalypse, Left 4 Dead 2 (L4D2) is the highly anticipated sequel to the award-winning Left 4 Dead, the #1 co-op game of 2008.

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.

You'll be putting these weapons to the test against (or playing as in Versus) three horrific and formidable new Special Infected. You'll also encounter five new “uncommon” common infected, including the terrifying Mudmen.

Helping to take L4D's frantic, action-packed gameplay to the next level is AI Director 2.0. This improved Director has the ability to procedurally change the weather you'll fight through and the pathways you'll take, in addition to tailoring the enemy population, effects, and sounds to match your performance. L4D2 promises a satisfying and uniquely challenging experience every time the game is played, custom-fitted to your style of play.

• Next generation co-op action gaming from the makers of Half-Life, Portal, Team Fortress and Counter-Strike.
• Over 20 new weapons & items headlined by over 10 melee weapons – axe, chainsaw, frying pan, baseball bat – allow you to get up close with the zombies
• New survivors. New Story. New dialogue. 
• Five expansive campaigns for co-operative, Versus and Survival game modes.
• An all new multiplayer mode.
• Uncommon common infected. Each of the five new campaigns contains at least one new “uncommon common” zombies which are exclusive to that campaign. 
• AI Director 2.0: Advanced technology dubbed “The AI Director” drove L4D's unique gameplay – customizing enemy population, effects, and music, based upon the players’ performance. L4D 2 features “The AI Director 2.0” which expands the Director’s ability to customize level layout, world objects, weather, and lighting to reflect different times of day.
• Stats, rankings, and awards system drives collaborative play

System Requirements

Windows

MINIMUM:

• OS: Windows® 7 32/64-bit / Vista 32/64 / XP
• Processor: Pentium 4 3.0GHz
• Memory: 2 GB RAM
• Graphics: Video card with 128 MB, Shader model 2.0. ATI X800, NVidia 6600 or better
• DirectX: Version 9.0c
• Storage: 13 GB available space
• Sound Card: DirectX 9.0c compatible sound card

RECOMMENDED:

• Processor: Intel core 2 duo 2.4GHz
• Memory: 2 GB RAM
• Graphics: Video Card Shader model 3.0. NVidia 7600, ATI X1600 or better
• DirectX: Version 9.0c
• Storage: 13 GB available space
• Sound Card: DirectX 9.0c compatible sound card
• OS: Windows® 7 32/64-bit / Vista 32/64 / XP

Mac

MINIMUM:

• OS: MacOS 10.7
• Processor: Dual core Intel processor, 2GHz or better
• Memory: 2 GB RAM
• Graphics: ATI Radeon 2400 or higher / NVIDIA 8600M or higher / Intel HD Graphics 3000
• Storage: 13 GB available space
• Additional Notes: Not supported: OS X 10.5.x, ATI X1600 or X1900 graphics, NVIDIA GeForce 7 graphics or Intel graphics less than Intel HD 3000.

SteamOS + Linux

MINIMUM:

• OS: Ubuntu 12.04
• Processor: Dual core from Intel or AMD at 2.8 GHz
• Memory: 2 GB RAM
• Graphics: nVidia GeForce 8600/9600GT, ATI/AMD Radeon HD2600/3600 (Graphic Drivers: nVidia 310, AMD 12.11), OpenGL 2.1
• Storage: 13 GB available space
• Sound Card: OpenAL Compatible Sound Card