Sweet! I like the idea of growing you undead army. At first I was just avoiding all the police and booking it to the car and getting frustrated that there was nothing leading me to where the car might be. Then I re-read the controls and started zombifiying everyone making it a more enjoyable experience.
I recommend changing the wording on your page since it makes it sound like the most important thing is to find the police car but there's no guide on how to find it. Also, growing your horde doesn't seem to be explained in such away, to me, that makes it be the main focus of this game. Maybe consider updating that too so that it is more clear. :D