Maurice in this guide youll find all the commands used to tweak the source engine
http://forums.steampowered.com/forums/showthread.php?t=623213&highlight=portal+950 and here youll find our experience with this commands, from Soldiers without borders to the world with love. http://groups.google.com/group/intel9x-gaming/search?group=intel9x-gaming&q=hl2+target -- 9xx SOLDIERS SANS FRONTIERS
