Half-Life: Xen's Horror is a Half-Life mod where you play as a guy named Ayden Farrell who discovers the lost facility named Orange Facility. A little more bio, Ayden discoverers some devastating and horrible experiments which gone wrong and with the collapse of the alien world Xen are making their way to the human world.
Reduce the volume of the light on top. It may not be so well illuminated but enhances the atmosphere x10 fold.
Ok