Wait, zombies run on it?.. Yes, and it makes the game quite hard to survive. If an alarm goes off and 5 or more zombies starts chasing after you and you try to run from them, you bump into more running zombies without being able to put any distance and the mob just grows bigger and bigger. You will eventually die, leaving a huge cluster of zombies in a random spot which will be unable to recover without a lot of guns. Since there are other users making the same mess there are several other 'clusters' created in town, and after the remaining part of the town is depleted there's no choice but to go to that danger zone, but it's impossible to clear the massive amount of running zombies with an melee weapon. If you enjoy the thrill it'll still be fun, so did I, but I kinda got tired of it after my 5th death.