A “bunker” can be any cover such as a wall, a building, a tree, or a barrier. Pretty much any obstacle that will keep you from getting hit by paint. “Cover” is a bunker that offers protection from enemy fire, like a thick tree. “Concealment” is protection from enemy eyes that may hide, but not necessarily protect you as Cover would, like smoke from a grenade or big leafy ferns. Hides you well, but not much ‘cover’. “Soft Cover” is cover that may deflect the shots and turn them into splatter or spray. Branches, brush and tall grass are typical soft cover. The enemy may see you, but the paintballs have a hard time getting through intact. The bad news is that if they hammer that soft cover with paintballs, one may eventually get through and the force of the paintballs will eventually wear a path through the soft cover.