Every sound in this is from the L4D2 folder.

For example, the piano at 0:18 is the first note of the Spitter's piano cue being played with my keyboard. Around 60-70 samples were used.

Get the MP3: http://www.mediafire.com/?3ujdyyyn4nq

MP3 mirror (thanks m00d!): http://m00d.net/mirror/Chris%20Lohr%20-%20L4D2%20Club%20Mix.mp3