Source Game Problem: Flashlight does not illuminate all surfaces correctly

This issue is currently being worked on, one workaround is to be sure the following console commands are set:

Open the console, then type:

 r_dynamic 1
 r_shadows 1
 r_newflashlight 0

NOTES: r_newflashlight 0 disables the current flashlight for computers without an ATI card, or some other advanced graphics cards. This will make your flashlight more like the flashlight Gordon used in Half-Life 1.