Your character automatically takes cover. Tap to have him leave cover to shoot. If enemies throw grenades, you can shoot them out of the air before they explode. Civilians are highlighted in green. Killing a civilian will end a combo streak and reduce your money. Some missions will fail if too many civilians are killed. Enemy targets are highlighted in red. Special enemies will momentarily have a white aura that turns red. The special enemies allow you to build up a combo meter that will drop if fail to kill them before they escape. Get combos to gain stars and other rewards. Aim for the head for faster kills and to keep combos running.