Movies and television programs shoot straight for the impression. You can SEE what’s going on and you don’t expect a reasonable explanation. There it is, so it must have happened somehow. You get swept up in the moment, and so the background for that moment doesn’t have to really make any sense.
Games, however, do – which is where many “Zombie Apocalypse” games run into trouble.
Your standard zombie apocalypse setting features hordes of zombies (generally rather stupid, likely infectious if they bite or scratch you, and somewhat awkward, but really not all THAT hard to destroy), a shortage of food, water, guns, ammo, and other supplies, and a small group of relatively random survivors.
Over the course of the movie, show, or game those random survivors will lose some members, and pick up other stragglers to replace them, while dealing with a series of zombie attacks and zombie sieges, making sorties against zombies, and venturing into zombie-overrun areas in search of supplies. During that time they will take out quite a lot of zombies – often at a ratio of dozens of zombies destroyed for every human character lost.
Yet somehow a relatively small – and thus seriously outnumbered – outbreak of those same zombies somewhere managed to overrun human civilization, apparently including all kinds of military outposts, organized areas, and remote locations. Sure, surprise and shock will help a bit – but if random survivors with little or no equipment can take out dozens of zombies each, well-prepared and trained types can reasonably be expected to take out even more. You can hardly argue that any setting that starts off resembling the real world will be particularly ignorant of zombies. How many zombie movies have YOU seen?
So… why didn’t the zombie apocalypse implode, leaving civilization more or less intact? Why are there so many zombies LEFT?
Movies and TV shows usually skip over that part – something of a pity since the original Night of the Living Dead actually covered that issue; the zombies rose, a nearby cemetery (apparently with an awful lot of fresh bodies in shallow graves for some reason) provided enough zombies to besiege a small farmhouse – but, in the morning an organized bunch of people with guns came through eliminating the zombies. Evidently in most areas there was shock, horror, some casualties – and then the methodical elimination of the zombies.
Honestly, that’s what I’d expect from humans. Humans didn’t get to be the sole surviving hominid species, or domesticate dozens of other species so as to turn them into walking snack food, or manage to take themselves off the instinctive prey species list for so many predators (by consistently killing the ones that attacked them until they bred that tendency out), or come to dominate the world, by being nice. Sure, humans can display many fine qualities – but a quick look at atrocities, crime statistics, warfare, interrogation, and punishment through history suggests that a pretty large chunk of the human population will soon rival the most ruthless of sociopaths if they feel endangered, vengeful, or immune to consequences.
What can we do about this? Well…
- An epidemic with a long incubation period could spread widely through the human population before countermeasures could be taken – potentially too far to stop – provided that it’s both easily transmitted and infectious for a reasonably large part of the incubation period. Of course, in this case, it’s virtually guaranteed to have already infected your survivors, and will spread through any group that gathers with no chance of stopping it. This might work for a short, and utterly hopeless, movie or game, but it’s not really going to work for a campaign or television series.
- If the zombies are virtually unstoppable they could overrun everyone – but unless they weaken rapidly for some reason, this means that the best that survivors can do is to hide. That’s not very interesting.
Basically, any kind of slow-rise scenario with zombies that random survivors can evade or handle in reasonable numbers during a campaign is not going to overwhelm human civilization unless you get really, REALLY, contrived about it. Even if your zombie-making agent works on the already-dead, there aren’t many bodies in shape to turn into zombies compared to the living population (unless your zombie-making agent can build zombies out of dust, in which case we’re back to “major acts of magic”).
So we need a fast rise scenario – one where an awful lot of people turn into zombies without being exposed to a zombie in the first place but in which some people – probably pretty much at random – are spared. It doesn’t really matter what the zombie-making agent is in this case (or why, or even if, it’s infectious; being wounded by a rotting corpse without good medical care may well give you some pretty horrible infections anyway). Bits of radioactive meteorite, strange gases, out-of-control nanotech, some terrible necromantic ritual, mother nature striking back… whatever. When you have enough zombies to start with, it doesn’t really matter if they’re infectious or not.
If you want to include the usual resource shortage, just make it a preexisting condition. Throw in a month of two of war (perhaps the zombies are the result of some bizarre weapon), or some nuclear strikes, or a smaller initial zombie-rising before the main event, and you can fairly readily justify any kind of supply shortage you like. Turn 90% of the population into zombies directly and you can quite reasonably expect them to take out most of the survivors; zombies being easy to outwit won’t do you much good when you’re sleeping next to someone who turns into a zombie in the night, or when you’re five years old and your parents suddenly turned into zombies, or in a lot of other situations. You want 1% surviving? One-tenth of one percent? One in a million? Pick the circumstances and time of the transformation appropriately, and you can justify pretty much any proportion of survivors to zombies that you like.
As a (fortunate!) side effect, this means that you can pretty much eliminate the players/characters who insist that THEY are living in a private fortress stockpiled with ten years worth of supplies and enough armaments to equip a special forces brigade. you can just ask them for a full inventory and then inform them that they were part of the 99% who just dropped dead spontaneously, and thus they should make a character from among the random folk who survived the initial transformations.
Wait, you still haven’t decided how your zombies work? Go back and look at Part I again – Powering Your Corpse.