Reduced bright lighting and tuned spec of the eyes for better reflection of the environment. Eyes have a cornea whose spec was too low and bright lighting was eating at the reflection.
Fix the spec on the casing of the bullets, the spec should inherit some of the colour of the diffuse. Use the pic you posted yourself as ref. Other than that, this looks ace :)
I also forgot to mention this earlier: that is only the diffuse. Here is the spec gloss (added to the alpha channel of the spec map in a 32-bit TGA format) normal
It's not the overall level of spec, its the difference in spec levels between wood, metal, and paint. right now the naked wood looks like it has the same finish as the painted parts.
The sliders are setting the maximum potential value of each attribute. this is then modulated by the spec/gloss map. I set the spec to 1 and the sharpness to 256 and rely on my maps to control the values.
Unity uses Spec/Gloss not Roughness/Metallic. I think they're inverted from each other. Make sure you're using Spec/Gloss if you're pushing it to Unity.