... anyway, did some work on the Tartarus, decided the hull seemed a bit plain, and am thinking that I may need to give this some more thought. Blah.
Spoiler
Not looking so hot right now.
So, here's my thoughts. I like the overall design, but it is missing some zing. For comparison, take a look at your Elysium sprite - the extra fine details make a huge difference. As an added bonus, having those silver metal-y bits makes the standard grey weapon mounts fit in better - right now, they're the only silver on the hull, and that makes them look out of place.
I'd also take a look at the sections I've outlined in red in the attached image - I'd consider making all of those similar structures, where there's a hole in the shell and some bubble of underlying structure coming to the surface; I'd also seriously consider putting in some silvery bits rather than the solid brown dome of the back one. This could also be a good place to attach ship system glows; for example, if the Tartarus gets maneuvering jets, these might be places to put those extra engine glows.
Edit: detached the image; no need to leave it there until some mod has to come by and clean up un-needed attached files. It served its purpose.