I've heard some people say that Sandstorm has some type of brownish film grain filter put over it (I'm saying this because the supposed command to disable it is Filmgrain=1 or -1), washing out the colours and making the game look all around ugly. Whatever it is, there should be an option to turn it off in the settings.
https://steamcommunity.com/app/581320/discussions/0/1736589520003964116
https://steamcommunity.com/app/581320/discussions/0/1736589520006377409/?l=english
The washed out brown look, whether a filter or not, isn't the best look for sandstorm. Pre-alpha and alpha footage (especially the reload mechanics video) showed a much better colour scheme and art direction that I think most people would prefer.