As revealed by PC Gamer's web site and on GameTrailers.com, both Left 4 Dead 1 and 2 will be getting The Sacrifice, a new three level campaign that tells the story of Left 4 Dead 1's original survivors before they meet up with Left 4 Dead 2's cast in the recent DLC The Passing. While The Passing shows us that (spoiler alert) Left 4 Dead 1's Bill is dead, The Sacrifice will allow players to change which character from the Left 4 Dead 1 cast actually bites it.
One of the cool things about Left 4 Dead 1's version of The Sacrifice is that it lets players try out the cool new melee and other weapons from Left 4 Dead 2. Left 4 Dead 2 players will also get Left 4 Dead 1's No Mercy campaign as an extra DLC download. In addition, there will be a massive 150 page online comic that will lead up to The Sacrifice's story that will start in September. It's being drawn by Michael Avon Oeming who is best known for his work on the Powers comic book series. GameTrailers.com revealed that Oeming is now actually on staff at Valve.
Gallery: Left 4 Dead 2 Screenshots