Good effort!
You're getting good at drawing these! It's great that you can spot your own errors (i.e. thin arms, short legs), but there is one thing that bothers me. The way you put the background in, it seems like it's a separate piece of art. It just doesn't seem like the robots actually standing on the ground. For that matter, you might want to work on your perspective a bit more. Other than that, you did a good job. Hell, if I could draw and color decently, I'd submit stuff(my art skills=4th grader). Overall, 4/5 & 7/10.