Honestly I think this cover would look much more somber and forlorn with less saturation, I'd lose the heavy grey bars on the top and bottom for something lighter and really tone down the map colours or make them dirty sand orange tinted. If you had the nuclear explosion as the major point of light and action and saturation it would really make it a focal point.

No, on second thought I'd keep the bars as they are but lose the bevel around them and lose the border around the map entirely letting it go right to the edge of the paper. An alternate solution to the colour thing is to do the thing that cameras do and have the map really very black with just hints of what is there with just the explosion. (like when you take a picture of something very bright like a welding arc).

I like the idea behind the cover, but it has to get a good look to it, or you're going to be right it won't compete well with buxom ladies shooting guns and squishing zombie faces with high-heeled thigh-highs (do they make covers like that anymore? They should...).