My tank is moving pretty decently. Gamepad controls are alright,
Spoiler:
however, when putting digital(keyboard) controls in, be sure to bind them to an axis instead of to an action. Binding them to an action only triggers the function for one frame(the one in which the key gets pressed, not giving enough momentum to the tank to move at all.
I put the stuff in spoiler tags, not sure if this is the type of discussion you want.