On the base plate I did a lot more work on the rust. Before hairspraying I stippled rhinos hide and ryza rust to create more variation in colour but neglected to on the marine to save time.I particularly like the shape of the rust spots. I think considering the size of the rust spots that they seem too smooth. When I think of large areas of rust like that I tend to think of more texture within the rust patches and also more color variation. This could be a little bit more of a red/orange/brown stipple in the interior of the the largest rust areas, or in spots where the rust would have been abraded.
I think the marine's head is too close in color to the body armour paint. So there isn't quite enough separation between the flesh and the armour.
The verdigris also isn't really working for me. It seems like it's layered in mostly for contrast but it looks pretty smooth and flat. On the studs of the powerfist and on the backpack is ends up looking more like bad OSL than oxidation. I'm a firm believer than verdigris should usually be painted with a brush because it is created by the action of water on a surface which an airbrush doesn't usually capture. Verdigris is also not that smooth unless the entire object has been submerged, there's a lot more striation.