Left 4 Dead 2 is a zombie survivor thrill ride offering a much larger game than the original featuring more co-operative campaigns more Versus campaigns new Survival maps and the new competitive game mode Scavenge. With the AI Director 2.0 L4D s dynamic gameplay is taken to the next level by giving the Director the ability to procedurally change weather effects world objects and pathways in addition to tailoring the enemy population effects and sounds to match the player s performance. The result is a unique game session custom fitted to provide a satisfying and uniquely challenging experience each time the game is played.