Well, as I've argued previously in various other threads, I don't divide things in this way. I don't claim my game-(design-)purposes are exhaustive either. There might be other paths I've failed to consider. But these ones are how I see it:
- Score & Achievement: What maps closest to "gamism". There is some kind of metric which measures success, whether "you must reach this height" or "you must finish this quickly" or otherwise, and clear results or events which you can wear like a badge of honor if you reach them (e.g. "I beat the Tomb of Annihilation" or "my group defeated a Tarrasque").
- Groundedness & Simulaiton: What maps closest to what I call "hard" "simulationism", that is, simulation in the "rules-as-physics" direction. There is an establishment of ground rules and understandable, cognizable world which does not change unless for established reasons, and play is driven primarily by posing situations or events and then responding to them through creative application of abilities and tools (e.g. materials, gear, allies, etc.)
- Concept & Emulation: This is the "other" kind of "simulationism", which never sat right with me as being lumped with the above. Here, instead of setting a ground floor, this establishes genre conventions which will be upheld (or possibly critiqued), in order to explore an idea, a concept, a social construction, etc., so that play can proceed by bringing to life a particular group or class of stories.
- Values & Issues: What maps closest to "narrativism". Players and GMs alike define what things matter to them, what drives their character(/the world's inhabitants, for the GM), what pushes things toward uncertain moments, and then play occurs by asking, and finding out, why and how those uncertain moments resolve, and in doing so, what subsequent uncertain moments result, generally with the idea that both characters and world will be changed by this process of resolution.
No two of these game-(design-)purposes is incompatible with any other in the abstract. All of them can prioritize "realism" or "verisimilitude". Though G&S is obviously the
most interested in that goal, it is neither exclusive to it, nor always the most important thing for it. Even G&S makes concessions to the inherently abstract nature of gaming, and may, under circumstances narrower than the others, even make sacrifices of "realism" in the name of making something
feel more grounded/natural/etc. despite actually
being less.
V&I is the newest kid on the block, though its roots trace back to pretty early on in TTRPGing--it just only got attention and intentional
development in the past like 20 years. S&A is unequivocally the oldest (having evolved out of wargaming), but G&S came right on its heels and has been frequently in tension with S&A ever since (and, ironically,
both often lay claim to the mantle of "realism"--but they mean different
things by "realism", one of the reasons I strongly dislike that term.) C&E is, in my experience, unfairly treated like a mere subset of G&S, when in fact the two are usually quite different in both goals and execution, only being similar at a
very high degree of abstraction--at which point
most of these game-(design-)purposes are fundamentally similar.
