You can also configure the chance per night for the apocalypse to happen. There is a message at 8:00 PM warning that the apocalypse might be coming, and a message if it doesn't happen. Both of those messages can be disabled. There is also a limit to the number of zombies that can spawn. If this number is anything under one there is no limit. If the "hardlimit" is over one, it will spawn only up to that many zombies.