Here are some old Gamma World related pictures drawn by my friends who played in a particularly long running campaign inspired by Dune and Robotech and Heavy Metal magazine and anything else we happened to be into at the time. These drawing would have been done (I'm guessing) in 1985 when we all around thirteen.
This last one was drawn by Yours Truly. I don't totally remember who the Gathian tribes were, but I do remember they has a cool looking city. I'm thinking they were some kind of cross between Logan's Run and the Robotech Masters.