I like the overall concept, but the damage is somewhat unrealistic, and the left leg normally would have given way from that many holes. You were a little generous in inflicting damage on that leg. I also noticed that the lazer thingies aren't solid, they look more like crayon smears. The arms seem a little to thin to support the guns. I see this as more of a rough draft than a final concept. I especially like the realisticality of the treads and such, as well as the acess panels in key places. The background is interesting as well, but it lacks detail. This is an exellent start.
The reviewer should also consider the fiction that this piece is inspired by. The machines in Battletech can have all of their armor stripped off and still function. Yes, even on the joints.
A spot of damage does not indicate that the laser completely penetrated the armor. If you jam a knife into your countertop, it leaves a mark, but doesn't always pass straight through the wood.
Lasers aren't solid. I feel that one should be pretty obvious.
Criticizing the lack of objects background, considering the context of it being a live fire testing ground, feels silly. This is not a draft. It is not a sketch. This is a finished product and it looks like a finished product.