walkthrough: first scout all the buildings you can and kill the zeds and retake the buildings.first the most important building is a hospital and lab.if any crazy scince guy is waiting at your gates dont let him in later he will take over your lab and 1 guy then he dies and make the lab a hostile building again.theres 3 ways to finnish this game.1 find the city hall 2repair the helicopter 3 research zombiesm cure .thats all and pls thumbs up my comment