Taking place after Blood Harvest and is considered to be the prologue to The Passing, as both campaigns are connected to each other.
#Left 4 dead 2 standalone patch 15.9 software
Valve attributed the short turnaround between the titles as a result of having many ideas to expand on the first game, but more than could be reasonably done through software patching or downloadable content.
#Left 4 dead 2 standalone patch 15.9 series
Left 4 Dead is a series of cooperative first-person shooter survival horror video games published by Valve.