The base is ruined and you have only few bullets against all the monsters coming. Your task is to hold your position until you find enough petrol to set off to evacuation zone. You have to go through another bases where you always find some petrol, new weapons and if lucky, some survivors. Repair your barricades but that costs time. Use traps if you have find the right parts. Be careful and hope you don't run out of ammo. I had some tense moments before I found Tesla gun, so think all the steps ahead.