Phantoon (Metroid Zero Mission Style)

[Zeph]

The shading in general. A lot of anti-aliasing and banding issues, though not as bad as the ship.
The dome on the top looks very sketchy, if you want that, then you definitely don't want it mirrored.

I think it would look better more dithered like the original, also look at how much texturing the original has compared to yours.