The colors, the concept, and the idea are great.
I think my only peeve is the composition, specifically on the bombs. They have varying sizes, but the coloring is the same throughout. It's hard to tell whether their sizes are different, or they're the same size, but different distances from the viewer. It would be great if there's a way you could show how large a bomb is compared to a building. To me it looks like we're right in front of the bombs and the city is at least 10 miles away in the distance.