i think the shield looks very good it just need some contrast on the colors. like make the darks darker and the lights lighter because the colors are too close.

However the structure of his body is very, well, how should i put this... not right.  His right arm its way to short and skinny and it looks like he couldn't hold that sword and his feet and legs are pointed to the left and right not the front how they normaly would be and his legs are also one size they aren't bigger at the thigh and smaller at the ankles.  the calf and knee should also be defined more since he is wearing tights.

Here are some threads on this sight that could help you:

http://www.wayofthepixel.net/pixelation/index.php?topic=4593.0

http://www.wayofthepixel.net/pixelation/index.php?topic=3467.0  (this one has a lot of good tools and tutorials in it along with references)

Update along with your update: The arm looks better because it doesn't just shrink really fast you can tell he had bulky clothes on, it fits his body better. You do need to fix the legs.

Well i think the guy running, being shot or whatever is very skinny and his head is a bit small.  you should also add a bow string to the bow and maybe some of the ladies left hand visible under her right arm like she was going to shoot the bow.
 

I think there needs to be more forehead and also look at the shape of the bones around the eyes they are a little odd. here is a good refrence

We can't do it for you you need to get it as good as you can so keep trying until you think it looks right to you or until you cant do anymore with it then maybe we can help you with minor issues that you can fix yourself. Maybe you can try drawing it with different colors for different parts of the body like draw an arm completely with black and then the body green and so on.  Even if you are not going to see the part of the arm still draw it, it will help with anatomy.

When you shade you should probably do all of the shading before going back and dithering just so you can make sure it looks ok and you dont have to waste alll your time redithering over and over again.  And if you are going to pick a light  source for a picture where he is not in a scene (such as he is standing under a street light)you really don't want to  pick right above his head. You should remember that this is sopposed to look 3D or as real as possible so your light source can be any where not just to the left,right, top or bottom it can be in the top left or something. 

Also you said your not here to talk about outlines but you really should focus on the outlines before you try and shade and you shouldn't have a black outline unless your drawing something that is going to be cartoony. Plus his anatomy should be fixed to before shading.  For his anatomy his legs are a little low and his arms don't have elbows.  also his hands look like they are in his pants not his pockets and his back is disfigured like OZ said.  You should try and look up some things online about drawing human anatomy.