My players have become entangled in a murder mystery in 1748 Prussia (using the Götterdämmerung system), and are trying to work out who the killer is while trying to both stay alive and avoid suspicion being directed their way. The outcome of this quest is rather open since they could basically give up and just run for the hills at any second (with the risk of being blamed for the murders).
Everything is set up in such a way that if the players can get the killer arrested by the authorities, they will be rewarded with an amount of money and an improved standing with the local law enforcement.
Problems arise if the players should take the law in their own hands and go after the killer in the pursuit of revenge. A monetary reward is not suitable should they find and kill the criminal, since their vigilante justice is pretty much murder in its own right. A simple skill point reward is always given on the completion of a "chapter" in my campaign and increasing such a reward is not appropriate either.
How should I reward my players for completing a quest in a way it was not supposed to be completed? Is it simply a failed quest since the optimal target was to make the killer face justice in court, or is the vigilante way just another way to completion?
Best Answer
Regardless of the system used, there should never be pre-defined win/lose conditions.
Your game should be about the characters and how they interact with the story you are setting as a backdrop. Thus, quests (or adventures or story arcs) should not have a win/lose condition predefined by the GM. The GM should be responsive to what the players characters do, whatever that is. A quest, or any other story arc, ends when the characters reach a conclusion that is suitable for them. That could be running away, killing everyone, or falling into despair and misery. As flamma kindly pointed out, the GM should reward players for fulfilling theirs objectives.
It is, of course, possible to have a list of predicted outcomes with rewards and punishments prepared in advance. However, in my experience this is useless but in the most common and uninteresting cases, your players will do something unexpected. The mantra "no plan survives contact with the enemy" applies here. Because I have a very limited time to spend writing game plots, I never bother with this. It has always proved to be an utter waste of my time that could be spend better elsewhere.
Lastly, having the "good ending" mean that the GM might push the players to said ending thus railroading the story where the GM wants it to go disregarding the players' wishes.
In your case, you have three potential endings all of which are good from a story point. It is how the players (and their characters) react to those that make the story interesting: Do they not care? Do they seek to upheld the Law, however corrupt that is? Or do they become avengers like Batman or The Punisher?