Aqui têm campanhas addon que eu recomendo que façam download. Classicos absolutos...

I Hate Mountains:
http://www.filefront.com/17869296/ihatemountains2-v1.2.zip/

Dead Before Dawn:
http://www.l4dmaps.com/details.php?file=7221

Detour Ahead:
http://www.l4dmaps.com/details.php?file=4094


Campanhas do l4d no l4d2:

Death Toll:
http://www.filefront.com/17172787/deathtolloriginal-v1.3.vpk/

Dead Air:
http://www.filefront.com/17189696/deadairoriginal_v3.7.vpk/

Esta campanha tem um problema com as escadas dos infectados especiais que espero que seja resolvida no proximo update à campanha.

Blood Harvest:
http://www.filefront.com/17143391/bloodharvestoriginal_v1.3.vpk/



Comando rebuild audio cache:
snd_rebuildaudiocache