Professor Coldheart asks how the core activity comes into play in the case of a generic rules set:
How does the above mesh with designing a setting-free or generic RPG? I'm thinking of the last iteration of Heroquest, which was divorced from the Glorantha setting. Also, I presume DramaSystem might see a standalone book at some point after Hillfolk is released. It would appear that these don't have a "core activity" as you define it - or do they?
With a single notable exception, generic rules sets appear as follow-up products to existing games. Hero grew out of Champions. D20 Modern was an alternate D&D build designed in part to show the system’s flexibility. Like Chaosium’s Basic Roleplaying, they may serve as reference documents for GMs who will use them as a basis for their own games. They are a chassis on which the game is built; it remains incomplete until someone creates the core activity for it.
HeroQuest might be described as a hybrid of both models. It serves as a reference document showing you how to build your series, effectively enlisting the GM a collaborator in a simple game design process. At the same time, it’s as much a supplement to previous iterations as a new and improved version of the rules. And with its Glorantha chapter, which arose from the realization that most people buying the game would be using it in its established world, it backgrounds but still expresses the classic Hero Wars/HeroQuest 1 core activity: you play heroes fighting to shape the turning of an age in a world where myth takes on fantastic reality.
Skulduggery likewise grows out of The Dying Earth Roleplaying Game and exists as a reference document (preserving that game’s system at a time when it seemed like Pelgrane would not continue the license) and a blueprint for making your own Skulduggery mini-games. Although it has done rather better than Simon expected, it was never expected to become a flagship game the way DERPG once was, or Trail of Cthulhu has become.
Implicit in this approach is the argument that generic games are a hard sell, both to customers and to players. That’s why the first DramaSystem game will be called Hillfolk and not DramaSystem, and will present itself on the basis of the core activity. Even if we wind up including additional settings in an extended appendix. Otherwise we’re trying to get you to adopt a game that communicates on an intellectual level but lacks an emotional hook. Even the issue of visual presentation depends on a core activity, from which the graphic designer and illustrators can tweak the imagination and weave an arresting look. The rules are so short and simple that they can reappear in follow-up products without raising buyer ire.
The aforementioned exception is, of course, GURPS. It essentially marketed itself on the strength of its design throughline. It was the one game where the core activity legitimately could be “You can do anything!” Again the supplements become the games that elaborate the rules chassis into a playable experience. This was possible at the time because it addressed a gap both in the market and in the state of the art. No one had done a ground-up design meant to be generic from the jump, as opposed to the usual serial iterations of a core rules system. Having filled that gap, it removed the necessity for anyone else to attempt the same. Thus the return to the iterative model.
This has gone long, and there are still some more questions to cover. Let me know if you’d prefer that I steam ahead, or stop along the way to answer queries like this one.