Use every means necessary to weaken the enemy army and cut off their retreat in Ambush. Place units strategically to shoot at the invading enemy and earn stars for upgrades. Click on units and place them in the green parts of the screen. When the enemy approaches, select 'fire' for your soldiers to start shooting. Make sure to replace fallen soldiers. You can also select air strikes to target specific groups of soldiers. Watch the waves of soldiers approach at the bottom of the screen.