I'll go first:
How to make doom a "horror game"
DarkDoomZ and Flashlight++ (the mods you need)
Open Flashlight++ Settings
Color -> Solid Red (if that is the name)
Sound Effect -> Night Vision Tick (HL: OP4)
Now for DarkDoomZ
Open DarkDoomZ Settings (once again)
Mode -> Crush
Setting -> Dismal
Now head over to "Advanced settings " n' do this
Sector Light Effects -> Remove
And finally (even though its not a setting for any of these mods) Begin with -nomonsters parameter and music set to 0
Preview:
Without mods=========================================================================
With these modsCongrats! you just made your doom experience "scary"
As always, credits go to the devs of these mods: Caligari87 and generic name guy
edit: oops, forgot some other stuff
Open console and type r_drawplayersprites 0
Then set HUD size to 0