The shapes and lineart are really nice! For colors: I think the issue is that you picked darker value of the same color when painting shadows. Shadows however are often not just grey, depending on light they may be blue, violett or dark red for example. I would play with those colors. Same goes for highlights, especially on metals since they reflect environment: try to use slightly more saturated light colors. I would also use slightly more saturated color for BG - it would throw you off less. | Artwod Feedback