Looks to me like your using the heavy metal texture from highend3d eh?
Well theres ways to make better metals you should check out.
About the overall shape, the position of the legs wouldnt be able to hold up the cockpit. It qwoudl fall over forward. The feet should be a little bigger IMO to help steady it. You might want to add somethign to show size, right now it could be 40ft tall or 40 inches. Hatches, handles, so on help. Details are a must on mechs(i know i need to take my own advice), and i found a good detail is the guns, get rid of single barrels and make chain guns. ^(or more) barrles belt fed.... that will add a few hours of modeling for you