But let’s look at that kind of mechanic for a minute:
These mechanics may or may not be a good addition to a game that has these three foundational elements already in place, but without these elements, they’re worse than useless: they will, I’d argue, actively drive you away from meaningful character play into superficial, genre-based portraiture.
To take Keys from The Shadow of Yesterday as an example. To the extent that Keys are supportive of this kind of play, they are so because (and only if) these other elements are in place.
These other elements are supported by TSOY (to some extent at least): the setting of The Shadow of Yesterday is rich with political and cultural material that can be used to create dilemma-filled situations and the procedures for resolving uncertainties definitely lead to consequential changes. As for the third element, I don’t think the text necessarily makes this clear enough, but play that doesn’t honor player choices (or play that is forced into a “party” approach) falls flat in this game.
Given these three foundational elements being in place, Keys, then, support and can act as an engine: they provide character motivations that intersect with the dilemma of the situation in unpredictable ways, further complicating the moral and psychological landscape; they also drive players to make individual choices that will likewise complicate things in a way that will highlight the specifics of each character through the way they differentiate each player character from the others.
Without those elements in place, however, Keys are at best a superficial addition (like giving bonus XP to players who use funny voices) and, in practice, end up being a serious distraction because people get the idea that the Keys (or similar mechanic) are where the possibility for characterization and thematic play come from, and the three, necessary foundational elements are ignored or underdeveloped.
(Historically, that is what I think happened within the design culture that started at the Forge and migrated to the Storygames forum: people got very excited about Key-like mechanics and lost track of the importance of what I am calling the three foundational elements. People familiar with Forge theory might recognize what I am describing as Vanilla Narrativism: a coinage that was not initially meant to be derogatory but rather merely descriptive (Vanilla meant as baseline but not boring), but which, like a lot of Forge jargon, picked up negative connotations.)
Lady Blackbird is a good example of a game where Keys become a distraction from thematically rich play: there we have a situation not drawn from genuine interest, but rather from things familiar to us as audiences of other media; the resolution procedures are easily massaged away from consequential outcomes; and the assumption of the scenario is that player character actions will only be honored to the extent that they do not take characters off the narrow path expected by the expected. Keys here do not support character-driven play: rather they act as prompts towards creating portraits familiar from other media and help pace the story in similarly generically familiar ways.
Ok - so why did I go through all of this?
Basically because I think achieving this kind of play is a lot simpler than many people think (simple in terms of “not requiring more mechanics than we’re used to from ‘traditional’ games). It may be difficult — or, rather, there’s definitely a learning curve: but Key-like incentivizing mechanics won’t get you through the learning curve any more quickly. They are just as likely to be obstacles to this kind of play. And I think the discussion around this kind of play/these kinds of games has lost track of this.