It happens a lot in tabletop roleplaying games: you have a certain mood and tone planned for a campaign, and the players have other ideas. I’m running a Promethean campaign, and I planned for it to be dark, desperate, and gritty. The players are approaching it much more comically. It’s dark humor, which works with the setting, but it’s not how I planned it.
There are two classic responses to this issue. The first is the author-is-king approach: refuse to go along, chastise or punish the characters, and mold them to Your Story. This, of course, ends with an adversarial player-game master relationship and probably some grumpy folks in your house where they can break your stuff if they want. The second response is the players-are-god approach: let the players have the sort of fun that they want to, and adapt accordingly. This can end in a muddled mess, where adversaries planned to be scary and bad end up being too hard to kill and trying too hard to be funny.
I’m trying to reach a middle ground. I’ll present the players with the world more-or-less as it was originally intended. Vampire princes will be grumpy, monsters will be scary. The players, however, can be as cheery and carefree about it as they want. I’ll feed them straight-men for their jokes all day long, including burly bikers named Jim and long-suffering, maybe over-indulgent vamp princes. But when it comes to conflict, I’ll expect them to match their humor with actions.
In a sense, I’m turning my game into a Marx Brothers film. The players aren’t nearly as silly or disruptive as Groucho, but I’m going to aim for the same feel: NPCs will play it straight, but indulge the PCs their jokes and play around a bit. As in Duck Soup, it may all end with the walls shot to pieces and the characters wisecracking about it, but I’m going to try and enable silly, humorous play within a darker, more serious framework.