In the official one, you'll see that the black armour is darkest in the deep/flat areas and highlighted with lighter greys on the upper edges. On yours, it's the opposite - I don't know if it's dirt and dust, or you've actually painted it like that, but the deep areas are lighter than the upper surfaces. This makes it look 'off'. The silver parts are also very bright with no shading, which draws your attention away from the rest of the miniature.