you need the new version update.
Version 2.0.4.1 (left4dead2)
Exe build: 11:29:53 Oct 1 2010 (4346) (550)
[youtube]k1nCxyZhhHM&feature=fvwk[/youtube]
The Sacrifice is the prequel to The Passing, and takes place from the L4D Survivors' perspective as they make their way South. In addition to advancing the story, The Sacrifice introduces a new style finale featuring Sacrificial Gameplay where players get to decide who will give their life so that others may live. In addition, those with Left 4 Dead 2 receive L4D's No Mercy campaign. Both campaigns are playable in Campaign, Versus, Survival, and Scavenge modes and both will feature the Left 4 Dead 2 Special Infected, items, and weapons. Yes, Zoey with a chainsaw!
also can we please update the adf server sniper