Screamernail was having trouble finishing a scenario called Marathon: Green, so I finished it. This is in tribute to him. It's Extermination, so return to the starting tile after killing everything.
This scenario uses the Differential Shading Checker plugin by Douchetower/W'rkncacnter, which should be checked by default. If the textures aren't defined/differentiated enough, simply adjust graphics settings until you get something like what you see in these preview images.