The Left 4 Dead soundtrack is easily accessible inside the folders of the PC version of the game and most of the tracks are properly tagged, so the only real work that went into compiling this soundtrack was splicing the various cues and a couple sound effects together. There isn't a whole lot a music in the game but for what it has, it's eerie and good.
The way I went about this for each infected; Boomer, Smoker, Hunter, Tank and Witch; was I mixed the warning cues of the infected with the themes you hear when an infected is attacking or has you pinned down. Otherwise, there would be too many short tracks on the album but I think it sounds pretty good the way it turned out.
Heh, some of the tracks can be.. well, uncomfortable to listen to on a casual basis. For example, I can't exactly see myself listening to "Clinging To Hell" on repeat on the way to work but there are some other well made tracks on here(Main Theme being my favorite) that are easy on the ears. So if you're looking for a good listen during Halloween, it's uploaded in 320kbps MP3.