You should really mention that the original linework isn't yours; in a lot of cases it could mean the difference between having this deleted by a mod, or even potentially getting you unscouted if a mod decides its art theft or that you're intentionally implying this is all your work. The best thing you can do is link to the linework artist, provided you know who it is. Good job on the shading and colors though, even if there is quite a bit of artifacting upon some scrutiny, the shading on the man looks to be largely consistent and does a lot to bring him out. Still I have to acknowledge your lack of acknowledgement on the linework and rate accordingly, props to that guy though for a really neat design.

Nice work..Does he have his own gravity field? Just curiously joking...