I’ve complained in the past about games that use mechanics to force a specific type of gameplay. While this certainly holds true when talking about the core of a game, there’s a lot of power to the idea. In fact it is actually a good thing, especially for themed games. Giving vampires an advantage to biting vs using a machine gun makes the players happy. If machine guns are always better, then everyone will just grab BARs and the parts of the game that focus on vampires will get drowned out.
That’s one of the big challenges for story games. They are free form story telling platforms. Think of it like having a group of friends tell a story one sentence at a time. You’re bound to have space aliens show up with rather uncomfortable probes when you get to a goofball in the group. Free form story games are a lot like this; and because there is nothing pulling players back to the genre, players will not always be motivated to work within the given world. It’s only by adding special rules for the genre that players are reminded to stay on task.
I find that it’s not general rules that accomplish this. It’s the specific actions that remind players keep the genre in mind. A Dragon Ball Z game is not DBZ because you told everyone they have to have yellow hair when they get angry. It’s a DBZ game because people launch Kamehameha’s at each other (By that I mean the energy ball. Although having a Hawaiian king launched at you would be pretty scary too). Maybe it’s a platitude, but it’s the little things that make the genre work in my experience.
I think the real reason why making genre specific rules is so important, though, is player expectations. They’re going to expect a rock-paper-scissors like relationship between genre specific concepts. Ghost’s can walk through walls but they can’t walk past salt, humans can’t hurt ghosts but they can wipe away the salt and help a ghost. Having these special rules make expectations for the genre set in stone and provide a best strategy. Supernatural fans pack their oak steaks when they fight demigods, but not when they fight demons. And with this, hopefully their existing knowledge of the genre helps with strategy. Almost like a measure of their expectations.
This can be hard for story games. The concept of “rules lite” relies on the understanding that more rules always bog the game down; but sometimes a genre wants the game to be bogged down. A story game could use a court scene as a back drop and most likely want to hurry through it. A few rules within the common mechanics and it’s over. Trial’s finished and the plot continues. However, A Law & Order fan game needs this court room process to take longer. It is the main focus of the game. So using genre specific rules can draw out the scene and use a strategy drawn off of player expectations.
Brand new RPGs are often written to do this, but this is a mistake. The core of the game gets wasted on a concept and is not pliable enough to use on others. This means that every player that wants to play this specific genre game has to learn new mechanics and a lot of new rules. It leaves the classic barrier of entry problem that rules lite games gracefully solve.
I believe the right answer is to simply create a supplements for your favorite systems. Apocalypse World is one game championing this. There are plenty of genre specific implementations of the game, and even small playbooks created just to modify the existing game to include parts of another genre. Fate is another great example.
But even a supplement is too much sometimes. One of the drawbacks of Apocalypse World is that you NEED playbooks to hit another Genre. Even SFX! creates a brand new rule book for every genre. This becomes a barrier of entry for players as well as GMs who either need to find their genre in existence or put more effort into game making than world building. This is why modding an existing system with house rules is the right answer for a lot of groups. Story games are great for this, you get to leverage the strengths of story games without the overhead of major game design or learning new systems.
So the point of all this is that once a story game’s core is done, you should never be afraid to add rules to enforce a type of play. Embrace it and work with player’s expectations to give them the genre they want.