( you can using grenade jump, but you are not supposed to ). Osprey is periodically dropping four marines behind electrified fence which you cannot get over. The open area has marines, an V-22 Osprey and the area is constantly bombarded with artillery. We've Got Hostiles ( map c1a3b ) / Marines They do always fall onto the ventilator and die. Above the ventilator is a hole with infinitely spawning headcrabs. There is a ventilation shaft through you which have to process to advance, inside is a horizontal ventilator that is spinning ( it will kill you if you don't crouch). The room with the flooded room and electricity. This is a list of locations sorted by game playtrough
( Holds true for every difficulty level ) Monsters/Enemies respawn only at certain locations.
