This config turns off some of postprossessing what makes the picture more clear. It turns off bloom, blur, grain and vignette.
To install extract clear_vision.cfg into
C:\Program Files (x86)\Steam\SteamApps\common\alien swarm\swarm\cfg
Edit newmapsettings.cfg by adding a line at the bottom of this file
exec clear_vision
This comment is currently awaiting admin approval, join now to view.