Hi Mike,
Your looking for a critique, but still none! After all, if not for critiques how would we improve, right! Well, I'll at least put in my two cents.
First the ground work- I would use like a Aves epoxy putty and spread it out over the base and use a wet medium stone and create some contour to the putty, then once putty sets up a bit, set figure in putty to create indentation for later placement when figure complete. After this is finished take some gravel or balast and sprinle over certain parts of ground loosely and then do the samre with static grass and spread it out in a couple of areas of the surface unevenly. Look at my ground work in my 'DAK' figure SBS and see what I did. Before the material is set in, apply a very light wash of glue/water. Once ground work set up. Paint the surface with, I use Tamiya acrylics, airbrushed on , and then gradually building the highlights by drybrushing earthtones, with Buff as my highest high light. Good ground work always improves the look of any painted figure.
The figure- As far as painting, I'm not sure if you're familiar with Shep Paines stop sign rule for painting. 1-5, being 1 as the highest high light and 5 being the deepest shadow, and 3 the base color. When ever approaching a figure I always keep the color highlights in mind. There's also the halo effect of light. Take a lamp and shine it down over a figure and this will show you where the the highlights and shadows set up the figure, keeping a mental image of this as you start painting, creating this three dimentional highlighting and shadowing with you painting. So, as far as the figure, I'm not sure if you paint wet on dry, but you could go back with these painting tips and add some more highlights and shadows to the figure, especially in the face. Also, cut in some seams on the clothing where you would normally see seams. As far as the rifle, It looks like it's as you may have heard before, floating. It doesn't look like there's much weight to it. I would have the rifle hang down, like it has some weight. Always, always, always make sure that the straps to this heavy rifle are tight. There's nothing worse than having something that looks like it should be weighted down, such as a rifle, but have loose straps. It kills the whole thing, IMO. One technique that I use for tight straps is first i'll place the weapon, then I'll apply one end of the lead foil to say the muzzle end of the gun and carefully, if going over the shoulder, apply a smidge of glue on the shoulder, and apply strap over that, keeping things tight, and then finally applying the end to the butt of the gun. These are just some fundamentals that would improve things immensely. Hope this helps.
Jim