Yep, it’s The Sacrifice.
Released in two versions: one for L4D1, and one for L4D2, both featuring 3 maps of pure atmospheric awesomeness.
The L4D2 version features all the new Special Infected, weapons, items, and much more, including the classic No Mercy.
Of course, Valve has one surprise left for tomorrow, and we have an exclusive little scoop: the surprise may be an announcement relating to other L4D1 campaigns being brought on L4D2.
L4D2 is also out now on the Mac, while L4D1 will be coming for the Mac sometime near Halloween.
The Sacrifice is also coming for the Xbox 360, in both versions.
Both games are now at an all-time low price of 4,75$. Yes, you heard me right.
The final issue of the Sacrifice Comic is also here.
The servers are under a lot of stress, so be patient, folks.
Here’s the official L4D blog post: http://www.l4d.com/blog/post.php?id=4434