The design is good enough but please give proper movement tracks to the unit, and then move the firing popcorn to the cannon nozzle; also, give it a portrait with a TC plane. The model also takes too much space in decay animation; make everything else disappear and perhaps keep the wheels.
AWAITING UPDATE until the issues are resolved.
Also, could you make it so the gun retracts when firing? You can do it by setting the cannon geoset to a new node that is parented to the tank, then you can easily make a custom attack animation by setting the said new node slightly backwards on the right timeframe of the attack animation.