Wow, looks pretty great to me. I like the crystal-fan things, and the end-caps on both the zeppelin & the "canoe" underneath.
I worry about the relative 'boxiness' of the balloon, though; like, I know you have to fit the guns on top, but it's rather unnatural how flat it is on top & bottom. Could use some rounding. The back should have some kind of spinning propeller, no? (otherwise, why all the fuss with all that big flappy machinery?). Finally, the balloon's texture is wrapped fine, but might be a little stretched.
Those are just my non-artsy-opinions, though. Looks cool; I'm curious, what is it for (race & project)?