Uniform...The colors don't look right for a German uniform, too green. Also, jack boots were black leather, not brown. So were the Y straps and his belt.
The base...first, cover the styrofoam hill completly with a base material. Blend the hill to the base more, there's a sharp deliniation between the hill and the grown around it. Add some texture to the base material with railroad ballast. Add more vegetation, such as shrubs and grasses. Don't paint your lichen the same color as the base.
Now the good stuff. You are on the way to a good tight little compositon here with a little more work and reseach.