Many games revolve around the idea of the heroes preventing an end of the world scenario, but I’ve often found the "end of the world" feel missing when hearing about, or playing, these types of games. I’d like to see it included more. How could an apocalypse affect the game you are currently running? Whether it is a looming disaster that the party is attempting to deter, a previous event that the world is slowly recovering from, or a moment far back in the landscape of time, an apocalypse has world shaking consequences that can greatly change the feel of your game.
A lot of adventures and campaigns have an end of the world element incorporated into them, but I’ve never found it all that prevalent. It is often overshadowed by the adventurers and what they must do to prevent it. Somewhere in our gamer minds, we know the party will win. If they don’t, even if it ends in a TPK, we rarely think beyond our characters’ failure. But what will their failure mean to the world?
If a game has a "Succeed or its curtains for the world" feel, there should be no reason not to make the consequences of failure relevant. If the party is defeated, or fails to stop the BBEG, have a narrative session where you describe the carnage that occurs because of their failure. If party members are still alive, let them narrate their own actions and roles in the final days. A player might want his paladin to fight on to the bitter end against the armies of the damned while a cyber-hacker might spend his final days spending all his ill gotten loot on physical pleasures. Even if you intend to give the party (or a the player’s new characters) another chance at it, knowing how bad it might get can incredibly alter the feel and immersion of the game.
The Final Days
One of my friends, a great Game Master named Edward Yarrus, ran a World of Darkness Gehenna game. Using a modified story out of the Vampire Gehenna book, and incorporating elements from the other W.o.D. games, he took the world from a healthy normal status quo to shattered and destroyed husk. One of the moments I will always remember from that game was thinking how awesome it was to see the world fall to pieces around our characters. It struck me that the dying world feel was absent from a lot of other games I had played in, or run, that had world-ending scenarios. It need not have been. Having it there would have made for a much more awesome game experience.
Even if the PCs were on their way to prevent it, how would the normal people react to the first tremors of an apocalyptic event? If armies of skeletons or Orcs appeared suddenly throughout the world, would the flood of refugees make the other nations take notice and try to rally against the common threat? If the sky turned purple as the dragons returned from their millennia long sleep, what would the reaction of people be? What new monsters and threats might be present in a modern or fantasy world during the final days? Are the very forces of nature a threat to the people during the end times? These kinds of factors will all depend on the reason and forces of a world ending event, but one thing is sure: The end of the world can be a reason to up the ante on a lot of standard gaming tropes.
The line between apocalypse soon and apocalypse now might be a very thing one, only visible once it has been crossed. The feel of an Apocalypse NOW! event has an element that an apocalypse soon event doesn’t:
An currently occurring apocalyptic event will certainly change the feel of a game. No matter what the source of the ending (Zombies , evil mage, religious , upheaval of the land , asteroid , nuclear , alien attack , misused science, Cthulu , etc.) things have changed for everyone. An apocalyptic event, by its nature, affects everyone in the world with maybe a few isolated exceptions. Will the people turn bloodthirsty to protect sources of food and shelter? How many sacrifices will people be forced to make to survive? A lot of these questions can be answered by a stroll through the Disaster movie section of your local video store. Disaster movies can give you great inspiration to include in an apocalypse themed game, even one set in a fantasy or sci-fi setting.
So the apocalypse has come and gone, and there were survivors. What a great place to set a game! For modern settings there are many options to look to for inspiration (The Fallout games, A Boy and his Dog, Mad Max, Mutant Chronicles, Brave New World, etc.) so I’m not going to go into this genre too deeply. Instead, I’m going to focus on what interesting things a post apocalyptic fantasy setting could yield.
A post-apocalyptic fantasy world might turn a lot of gaming tropes on their head. What parts of civilization are left? Would a fantasy setting merely regress to aConan The Barbarian type of world with more savagery and less civilization? Would any remnants of the old countries or civilizations remain? If magic was a big part of the world ending event then monsters may have mutated into strange unknowable configurations, or maybe magic doesn’t have the same effect it previously had. Who in the new world will be considered the strongest – those who can fight or those who know how to survive off the new land?
While not strictly an apocalypse, the great war in the world of Eberron is a great example of world changing events. A whole section of the world was destroyed and healing no longer works there. For an actual apocalypse the changes that might occur in the lands and the people could be massive. Doing this to a world can be great fun. Take the map from a published setting and redraw it for post-apocalyptic times. Think about what organizations might have been winnowed down and had to merge to survive. A recent apocalypse can give you a reason to rewrite any and every thing about a world setting.
Apocalypse A LONG TIME AGO!
 So maybe an apocalyptic event happened, but it was so long ago that none in the current age remember it. This can provide a lot of interesting options for your game. Ancient magic and technology might be available for those who raid dungeons. The gods that are worshipped today may be the remembered names of leaders and fictional heroes of the previous age. You can even build a current fantasy setting overtop of the bones of earth that was and have a lot of interesting reactions from the players when they encounter a subway tunnel or find vine-covered skyscrapers in the jungle.
Many sci-fi properties have elements of an apocalypse as part of their backgrounds. The world of Firefly has the earth as a lost homeland, Krypton was destroyed so that earth could have superman, and the events in both Battlestar Galacticas are set into motion because the worlds of man are destroyed.
These are just a few ideas about how apocalyptic events can affect a game. There are a lot of ways that an apocalyptic event can be implemented into an already running game or be an element for a new campaign. There are also a lot of great resources out there to look at for more ideas. Here is a quick list:
- Martin’s Review of Alpha Omega (A Sci-Fi world that rebuilt from an apocalypse) 
- Free Post-Apocalyptic RPGs 
- A List Of Apocalyptic Articles From Geek Emporium  (from Scott’s Around The Web In Eighty Clicks Article )
- Chatty DM’s Look At The Apocalyptic Trope 
- Wikipedia’s List of Post-Apocalyptic Fiction 
- Desolation RPG – A nifty looking (I’ve not done more than look at the website ) Fantasy-Post Apocalyptic Setting I found while looking for more links. 
So, what do you think about apocalyptic events in RPGs? Have you ever run something with an actual apocalyptic element or feel? What are some of your favorite apocalyptic games or movies to draw inspiration from? I’m a huge fan of all things post-apocalyptic, so feel free to share anything PA, I’m always looking for new movies, books, and games.