Protect Zone 2

Sometimes you can not save the whole world, but you can help it if you manage to protect an important lab in which scientists are looking for a solution to the current problem. It's not in your interest how to deal with an alien invasion, and you would not understand it anyway. So you do what you know the best and it is controlling your weapons. Monsters know they must destroy the lab, but they will not pass through you. Or do they? Protect the zone and do not let the monsters kill you. Do not cross over the red line at any cost, because you get into a dangerous zone and you immediately die. Have fun.