Looks like you tried to get something between square and cylindrical. Doesn't work too well, though. Back half big picture doesn't match the rest; try making it more cylindrical, or at least make a smoother transition from roundish to squarish.
Also, by the looks of it, no one would be able to see out of that bridge to the front through that arc and, more importantly, the thing in front of the arc. In fact, I actually don't see the point of that big "clamp" thing in the front; while it does serve to make the ship look bulkier, it also looks out of place.
Nose most assuredly needs work, but others have covered that.
