Capturing high-level nests.

With a machine gun that has an attack of 8 and expert artillery +7 units, any defensive position can be taken except for Phoenix nests. The tactic is simple: we use the machine gun to eliminate units while they kill our single units. Our goal is to reduce the number of enemy units to 2 before they start targeting the ballista. In the beginning, we use single units to shield the ballista, and we slowly move one single unit to the far lower corner. As a result, when the single units are gone, the last one will be out of range in one turn, and the machine gun will start destroying it. The machine gun will win – profit.