Left 4 Dead 2 is the second game in the bestselling co-op shooter Left 4 Dead franchise developed by Valve Corporation.
Development of the game began shortly after the completion of the first game. The game has 40% more dialogue than the first installment, with 7,800 individual lines.The developers also developed new techniques that both allowed variations in characters and zombies, but used significantly less memory than Left 4 Dead.
Left 4 Dead 2 was marketed with a massive $25 million campaign, beating the $10 million marketing of the first game. Sales and reviews were positive, with praise towards the detail and new weapons added to the already great action.In fact, Forbes reported that the game had sold more than 4 million copies by the end of 2010.