Toggle SweetFX on/off = `(~) = tilde key (disable "developer console" in-game or change toggle Key) 

Extract SweetFX into the following directories:

Half-Life 2 = \Steam\steamapps\common\Half-Life 2\bin\

If you have any issues, diable in-game AA, should work fine tho, did for me, your choice as always to 
use SweetFX SMAA or in-game AA, open "SweetFX_Settings.txt" change "#define USE_SMAA_ANTIALIASING 0" to "1"



