Thanks, Jason. Most of the interior is hollow, with the sides and top being 2 to 3 plates thick (to make it look more pieced together on a large scale). While the legs look thin, they are actually not articulated, and are very strong. Anchoring them to a baseplate helped, too.
I am most proud of the maxi minigun. I tried hard to make it to look functional (which unfortunately makes it rather weak structurally speaking). The quad mounted gun on the opposite side doesn't look too bad, either. Oh, I think the name is a good play on words.