it looks pretty cool so far, but I do have a slight problem with it. What bothers me is maybe just the camera angle, but there seems like there is way too much tank tread in the image. I think if you built up the top part under the canon, and added some detail to the turret, and the front skirt of the tank, it would just make it a bit more interesting. Plus I think it would just make it look a bit more complete. Only my 2 cents.

Off to a good start though, do you have any concepts you are looking at for the environment?
-Z