Mutation is called "Universal Downpour"This is a mutation that tries to port the storm from Hard Rain to any map the mutation is played on including custom maps(the one features in the screenshots is my campaign 4 Sided Coin).Also includes settings in ems/unirain/settings.nut. What they do is in the discussion pageScript version that works with all gamemodesThe full list of changes are:-The storm from Hard Rain is in any map-Rain is added to all maps-Fog is set to Hard Rain's colours-Skybox is set to Hard Rain's-Witches always sit-Colour correction is set to Hard Rain's-All precipitation is turned into rain (like Dead Air's failling ash)-Storm coming responses are added to L4D1 survivorsDue to this being a script and not a map change, there are many issues and drawbacks:-The rain disappears from certain angles-Lighting is unchanged so many maps will look weird, especially those set in the day like Dead Center or The Parish-The fog change isn't seamless