I think that it is fair to say that most children play the “don’t touch the floor; it’s lava” game as children. I know that I did. No one taught me this game. I had never heard of a friend playing this game. I had no older siblings who played this game. It was a fun exercise and, in its own small way, helps to build survival skills. While the “lava” part is due to the expanse of human knowledge and scenarios seen on television, that kind of game is almost instinctual.
One of the purposes of play, particularly as children, is to build survival skills (and to practice social interaction, of course).
There is a lot of speculation about why people find zombie apocalypse stories so fascinating and appealing. Some say that it is because, symbolically, it has to do with anything from 9/11 to living in a world that has nuclear and biological weapons. Some say that it’s a secular way of telling a Rapture story, while others say that it is because we all have the potential to become the enemies of our neighbors and family members.
I am sure that bits and pieces of those are factors in a lot of zombie apocalypse stories. In some cases they might influence writers. In other cases, they might subconsciously influence readers and viewers and gamers to enjoy the subject matter.
Personally? I think that it partially goes back to the basics: practicing survival skills through learning and play. Most of the people who enjoy zombie apocalypse fiction make plans for what they would do in such a situation. Would they fortify their homes or a friend’s home? Whom would they bring? What would they bring? How would they protect themselves along the way?
These questions are applicable in a lot of situations that are, while unlikely, more probable than hordes of slow-moving undead that are ..
.. ravenous for the flesh of the living. Whether it’s a massive blackout and major cities are destroyed (like in the cult favorite television series Jericho) or North Koreans are parachuting into the Northwestern United States to invade (which sounds like the shortest war ever. Also, physically, the shortest army ever. North Koreans are notable shorter than South Koreans because North Korea is the worst), people think about horrible things that could actually happen. If there were a massive biological attack or major cities were contaminated by nuclear explosions, what would people do? What would they bring, and whom would they bring with them?
Planning for a zombie apocalypse is just a more interesting way of planning for the same thing.
There is, however, an even simpler explanation for why zombie films are so popular: people love interesting stories. And there are a lot of interesting stories told in video games in which various forms of undead, categorized as zombies, are the primary threat. And because zombies are typically unintelligent, slow-moving, and particularly dangerous because of their numbers rather than as individuals, they make very convenient tools. Any writer knows that making a truly malevolent enemy too smart or too powerful makes the protagonists fairly unbelievable. I mean, zombies are disorganized, instinct-driven, slow-moving hungerers. For them, taking over the world is just what happened—like when mold “conquers” an entire loaf of bread. A story in which vampires—fast, strong, cunning, intelligent, and potentially well-organized predators—take over the world would be an entirely different scenario and, quite frankly, it might be more difficult to believe that there are still that many groups of survivors out and about. The same applies to overt alien invasion scenarios.
But zombies? Zombies do not figure out your strategy. Shooting them might attract more, but they will not set up ambushes for you. Most of surviving in a zombie-infested wasteland is simply surviving on your own, without modern conveniences. And not getting cornered by hordes of hungry predators.
It’s an interesting setting for a lot of different stories.