I like the blocky original more than the newer version. I have nothing against more interesting / complex forms, but currently you overshaded the edges that it looks more like plastic than metal. Use harder edges. The entrance on the top of the tank is better in the newer version, tho.
I like your small tanks. I don't remember the original very well, but I tried an edit to show how I would translate the bigger version. I altered some stuff which I don't remember, but basically I just tried to make the whole thing more boxy. I toned down some AA, removed outer AA, flattened areas, remade the barrel, straightened some edges, added a detail to the wheels to show some movement and removed all internal, black lines [
edit: I like the idea with breaking the outline at the bottom, like really squeezing the tank into the ground]. I didn't remake the entrence on the top, because first I thought it was an eye (kind of an emblem), but I would alter that too. One last thing: Don't change the shading of the bumping parts in each frame, I think it doesn't look right - imho. Well, just look at edit. I hope I could help you a bit. Have phun!
