Too hard.
Sure, I can shoot like twice a second, but only about 5% of the shots actually hit the target. With the way you have it set up, basically what the player has to do is draw a line from the tank to the target...WHILE the tank is moving, so you actually have to draw a line from where the tank WILL be to the target, WHILE you're moving around and dodging bullets. You can't draw the line all the way from the tank to the target, because that takes too much time; you can't stay close, because then you get shot; and if you just try drawing the line near the target, well, it's too hard to judge. Basically it's too hard.