First, let's make a note of the "change log" up above in the description and the "updated" note below that. This first came out in 2009 and was last updated in 2010. That being said, to answer your question, yes, this was the original one from the first Left 4 Dead. Ausimus was one of the first, along with 1SG Heartless, to start porting the original Left 4 Dead's campaigns before Valve did. However, as you'd notice by the previous comments, due to age and many game updates, this campaign has become some what broken. Unfortunately many people here often don't read or take note of the age of campaigns and just simply expect things to always work. Anyway, if you're looking for the original Left 4 Dead's No Mercy, I have one on my account, so your comment is good timing.