The shades and coloring: good! That rock wall's details were just oOo/

Perspective and some proportions: not so good

I don't think there are anatomy problems but that red guy's eyes look weird, like his sight isn't catching anything at all, for short his gaze looks lost.

The bag doesn't have much of the shape of a bag, it kinda looks like a rock with a branch at his side

I think the tree behind the guy pointing with his gun should have larger branches because its the nearest tree to those two. Just to have in mind with the perspective.

The clouds could use more work cause they look more like blue smoke than fluffy and white cotton.

Now the worst thing i see with this artwork are the utility poles far behind, your started with a good perspective from the right but when you got to the left, you lost it and started again, ruining that nice balance you got at the begining. Also this white light is supposed to be sunlight or something? Cause' i can't tell what it is :/

The problems you got here are mostly with the perspective and some shapes but the coloring was really good, I also loved the pose you gave those characters, they made me feel like I was in the battlefield with them! <3