Warning - while you were typing a new reply has been posted. You may wish to review your post. times 3 but this is still pretty valid i think
I don't agree I say definitely not going about it the right way!
You should be giving it crisp edges but you don't need to compromise the entire shape of the tank just build on it. I made a very minor edit to reiterate some points made by Evil-Ville you may have overlooked and bring up some points more clearly by others. Firstly palette change, yours is looking ok, but i do miss the green tones (the edit hasn't got exciting colours but it allows for more subtlety with the interlace). Secondly and this is probably one of my main points the shape has just become flat squares and all perspective has been lost. This problem may have actually been translated from Evil-Ville's edit, if you look at the shape of the side
It's actually poking out towards us a bit too much as if we are head on to the side of it as oppose to on an angle. I think everyone is fine with round parts but just make them crisp (as is in the original between the tracks for instance). to help support the fact that it is metal add lighting effects such as refractions. Also the dithering on dark areas can look very off such as in the tracks, either elude to the presence of more within it by distinguishing the general shape of cogs etc. as seen in my edit, or show it straight out like Evil-Ville's.
I know my edit isn't to pretty but i hope it helps.
