Kill 3 targets with 1 grenade. (10 G)

To unlock this achievement, you need to kill 3 targets with just 1 grenade. A good place to do this is during the mission Salvation, after you reach the church and are discovered. Immediately upon gaining control after the cutscene, look left and 5 enemies will run out of a door and take position behind various pillars. Try to throw a grenade somewhere in the middle of them all and kill at least 3 to unlock this achievement.