This are the technics to weaken enemies.(bridgehead)
1.get mages to the left side to defend ur left side tower.
2.get tankers and other dex hero to the right side.
3.send ur tankers to the most right side and fight the enemie's army(not Heros)
4.after the tankers get their str hammer, ask them to come back to base.
5.send 1 invisible hero and one dex hero to the middle of the most ride side road
and fight the enemie's army.
6.get the 2 hero to U-turn and ambush the enemie hero.
7.when the hero is distracted or dead, send ur tankers to destroy the enemie's tower.
8.do the same on the left side.