Here is a once top secret film of an H-Bomb detonated 400 Kilometers above the earth. After the first 5 min you can skip to 14 min to see different explosion stills. Its amazing stuff and might be useful for nuke explosion in the game. Even if you are not going for realism. http://www.youtube.com/watch?v=KZoic9vg1fw&feature=player_embedded#!
