In tribute to the end of my Millennium reviews (give or take that final bit left over in The X-Files), let's talk about blowing up your campaign world.
-It's memorable as hell.
-In bleak game settings like Call of Cthulhu, Cyberpunk or Stormbringer, it may actually be a satisfying way to end things.
-No take-backs, no attempts at returning to the game, full closure.
Of course, there are opposite drawbacks:
-Might leave a sour taste in players' mouths if they weren't on board with the idea.
-Might not fit the tone of the campaign.
-Kills off everyone and everything, leaving nothing for a sequel.
Of course, simply being open to this could lead to it without it being planned. Some scenarios invite the end of the world; it's just that the PCs are meant to prevent it. But what if they fail? In long-running campaigns, the GM will come up with some cop-out. The forces of evil fail all by themselves, or the heroes get a second chance somehow. But what if you go with it? You failed, world ends. A spectacular failure that will become part of the gaming group's campfire tales. Surely!
And it doesn't even have to be the GameMaster's fault. Though settings are usually large and expansive, the Player Characters' reality is probably much smaller. That puts the match in the players' hands. They couldn't blow up the United Federation of Planets, but they can set their ship's self-destruct. That's their whole world. You summon Cthulhu to eat cultists that have infiltrated your university (there it goes with you in it). To stop an evil Corporate plan, you wipe the Internet out... from the inside. It doesn't even have to explosive. If you eliminate a key element of the campaign world, you've essentially blown it up. Somehow killed the Force? Neutralized all magic? Wiped out the robot overlords for good? It's well and truly done.
But is it the end? Not necessarily. The end of an era is the start of another. From the ashes of your own game world can rise the Phoenix of the next. New PCs walking in the footsteps of the old, perhaps centuries apart, perhaps the next day. How quickly that military campaign turned into Mad Max!
But do you have the guts to push that button?