I swear tiger tanks in particular are unkillable by antyhing but arty and anti tank mines.
I had a 50xp sherman, 10xp at gun, and a 0xp at.
The tiger stood at the top of the screen for 7 waves.
My sherman missed 12 times, my at guns missed 6 times, and the tiger turned and destroyed all three with three shots.
Your armies can move in any direction. Just like you make an attack, you can tell your armies to move backwards.