I know that the right track and wheels look off. and alot of details still need to be set. I just need to contribute sum more ideas.
Looking great so far, some ideas:
It's apparent where you've repositioned the gun of the tank so I'd make to sure to keep working over that area.
The inside of the barrel is currently pitch black, make sure you think about all the light that would bounce in there.
Also it's not easy to tell whether the turret is twisted away from us or whether the origin of the barrel and the area above it are aligned correctly.
Nice work so far.
I think the turret needs a lot of work - it seems too flat and squashed. Needs to be a lot taller.
The overall picture is undynamic (spelling?) for me
Why not positioning the turret turned to something, why not playing with its ability to cross different heights with ease!?
Anyway, good characteristics of this tank!