First couple of rounds do whatever you want to do (i would recommend sticking with the pistol and knife" at the end of round 4 open the downstairs door, buy the smg in that room if dogs stay in that room, if not open up the door in that room and go buy ak74 and camp the gate, at about the end of round 7 open the gate. this is where you will be camping DO NOT OPEN THE DOOR IN THAT ROOM. have 2 people posted up on the windows in this room and 2 people watching the stairs you can make it very far with this strategy if you need to upgrade just make a crawler and run go upgrade get perks do w/e

Hope this helps. =]