You don't, all campaigns are playable when you start Left 4 Dead 2.
It is a Key that will unlock the Left 4 Dead 2 in your steam library
Black. Guy
What u have to do is go to left 4 dead 2 and search for sacrifice and the passing and you have to buy the missions and if u don't want to then you have to get an account and play it online
You can purchase The Sacrifice DLC for Left 4 Dead 2, which has you play as characters from the first game. Additionally, you can put character skins of the original characters onto the characters of Left 4 Dead 2 (Only in the PC version)
it is in an update so update your version on xbox live to play it
it will be unlock and then unlock march
he will sacrifice and this coming 2011 they will make a movie but there is no bill because he is dead
The Sacrifice for left 4 dead 1 & 2 come out on October 5, 2010 so hurry up mofos!
Left 4 Dead 2!!
No
(CAUTION: This answer contains information that may spoil the campaign(s) if you have not yet played them.) They meet in between the Left 4 Dead 2 campaigns Dead Center and Dark Carnival in a download-able campaign called "The Passing", which is soon after the campaign for both Left 4 Dead 1 & 2, The Sacrifice. The Left 4 Dead 2 survivors are driving through an infected town and the bridge is out, Francis or Zoey will tell you that you have to gas up a generator to get across because it has no energy left from when they raised it. Louis has a hurt leg so they can't leave him alone, and Bill got taken out by a few tanks, you will see the bloody result in the room of the scene. In The Sacrifice, where you play as the original survivors, any one of the survivors can sacrifice themselves to restart the malfunctioned generator to raise the bridge, but it will always appear as Bill in The Passing.
Yes there is split screen for left 4 dead 2.