I recommend upgrading 3 things first: Speed, so the people can't outrun the zombies, lifespan, so they have time to kill more people, infection chance so it's more likely to have a zombie rise up.
OMG!!!!!!!! 25,000+ AND NOT A TURTLE ON THE FLOOR!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
If you want a kill, you have to follow people around and scare them so much, they jump out a window. What REALLY gets 'em is the hands breaking through dish.