The comic is part of Valve’s experiment to release different forms of media based on their games and see how people like them. The Sacrifice will connect the story at the end of Left 4 Dead to “The Passing”, DLC for Left 4 Dead 2 in which the characters of each game meet up with one another. This is Part 1 of the comic, with a new part being released every week until October 5th, when a playable version of “The Sacrifice” will be released as DLC for both the Left 4 Dead games.
The comic is a quick read and relies a lot upon the clear-cut characterization of each ingame character. Nothing too in depth or complex, but I still look forward to taking fifteen minutes a week to read each new issue. My opinion is that like any cross media canon, even if it is created by the same developers, something of the original medium is lost when the story and characters are expanded. In this case I welcome the high quality of the content, but the original loose plot of Left 4 Dead is sort of a story in itself. It was meant to be a parody, and just adding on more typical zombie apocalypse content is not necessarily that interesting to me.
Edit: Darn Valve and proving me very wrong! I just read part 2 and the story is really picking up and had me both sad and happy at various points. While reading I was thinking, man, it would be cool to play that. Then I remembered that will soon be possible. Looking forward to part 3.