When I approached them from behind cover they seemed to not move at all.
If they haven't seen you, they should remain on guard indefinitely. If you blow up a building they'll also rotate to point in the general direction.
This becomes a problem because the tanks are never able to see you. I managed to ambush them and I didn't get hit by a tank once. It's probably something broken on my game though, I'll download it again and see if that fixes it.
That's very strange, do they even react at all? They should turn to fire at you if you hit them or come between their 120 degree cone of vision/where the turret is facing.
Well, all in all I have to say (again) that this game is really awesome, and I wish there was more of it/like it. I can't wait to see what the future holds for this game. Thanks for reading.
Thanks again!