Players try their best to change the worlds they play in. However, that may not always lead to the results they expect. This is a bit of a difficult topic though. While this makes sense, players don't often like seeing their actions lead to ruin. The question that remains is how do we handle it then? How do we handle bad outcomes and bad endings? This piece is the results of my thoughts on the matter.
Is It A Problem?
The first question that comes up as a result of this line of thinking is whether or not a bad ending is something that is inherently a bad thing. When I say that, I mean an ending where the players don't quite accomplish what they set out to do. They fell short. They may have made great changes that in the long run make all the difference, but it might not feel like enough. Again, like I've said so many times before, I think this will depend heavily on your group. Having a deserved bad ending could very well be what players expect and want. It's the other side of being able to influence the world they are playing in. However, in these situations the actions of players still influence the ending. It's just that the result is far from desirable. On the other hand, some players would prefer that they fell short of their victory instead of actively resulting in a worse situation. What this means can vary greatly as well. It could be that by failing their goal things lead to a bad outcome but they were close to accomplishing it, or it could mean that the outcome, while better than where things started, was less than what they had hoped to achieve.
Regardless of the outcome that results, it needs to feel earned. This is quite the nebulous term, just like what a bad ending really is, and what feels earned will depend on your group. In some circumstances and in some groups, a “good ending” may seem too far fetched. They are expecting something bitter sweet. Others might expect that if they do things right and try hard enough, they'll still be able to pull off a perfect ending. It also depends on the kind of campaign you are running. Having an ending that breaks the tone cultivated through the rest of the campaign probably won't feel earned. It's really more of an art than a science like many elements of tabletop gaming.
Still Leaving Their Mark
I've touched on this idea lightly, but I also feel it needs to be addressed directly. Just because things didn't go as planned doesn't mean that the players didn't leave a mark on the story. In fact, if you are playing a tabletop game and the players didn't leave a mark on the events of the campaign in some way, I'd be very surprised. It's in the nature of collaborative story telling that players will shape events no matter how hard you try to plan things. Even if things lead to disaster it should be the player's disaster. Simply leading to the same disaster probably won't be satisfying.
The Classic Bitter Sweet
The safest approach for a “bad ending” is to aim for a bitter sweet one. The players still influenced events and lead to outcomes, but didn't get everything that they wanted. This involves letting players leave their mark, but also letting them succeed to some extent. It's that combination of failure and success that tends to make this kind of ending palatable and often seeming like the most realistic outcome of events. Not every ending will require this, of course, but when talking about bad endings it's one type that deserves to be mentioned specifically.
The Importance of Consequence
All of this feeds back into the idea of consequences for actions. The players acted. This leads to results. These results lead to the ending. If they have failed, that ending will be a bad one. The specifics and the means by which this chain gets created leaves a lot of freedom, but maintaining this chain in some way is generally a good idea. The next campaign could be trying to clean up the mistakes of their previous characters, or it could be tackling the same campaign knowing their previous faults. There are a lot of things that can happen here. However, the idea that leads us to this point, forces us to thinking about this topic, and makes bad endings a viable way to end a campaign is consequence. And these consequences should be earned and shaped by the players.