Is there a meaningful distinction to be made between the system and the content?

[PhoenixPhyre]

As I see it, a TTRPG "rule-set" consists of two pieces. The system and the content. One tells you how to resolve in-game actions; the other gives pieces of various size with which to play.

At one extreme (?) are games like Fate, where the core books are almost entirely system. They tell you how to build content, but they don't provide things like settings, stock NPCs, "PC builds", or scenarios. Effectively, the content and the system are decoupled and you have to provide your own.

Much further toward the content-heavy/highly-coupled end are things like the Storyteller games (Vampire, etc), which from what I understand are so tightly linked with the provided world-building content, etc that it's hard to extract a system that can be applied elsewhere, at least beyond the "roll d10s, count successes" basics. Or Shadowrun, where the world is tightly coupled to the mechanics and vice versa.

In a different place are the modular "generic" systems such as GURPS, where they provide a lot of content in the form of rules/"powers" (ie things to spend build points on) but it's all modular and you end up building the worlds around it.

In the middle are (in different locations) the various D&D's, which have implied world constraints and lots and lots of content, but which also have a framework on which the content is built and a strong tradition of homebrew at all levels.

I've heard that the culture of The Dark Eye (sorry, my german isn't good enough to get the real spelling) is extremely top-down content-driven--you're basically playing in fixed modules where you don't have much freedom to change things and there's a strong meta-plot. But that may be a wrong assumption.

Does this idea make any sense to anyone else? Personally, I like a balance. I need the flexibility to come up with my own content (I dislike pre-written modules and being forced into someone else's setting as a DM) but I also want a broad palette of pre-generated things like stat blocks, spells, abilities, etc to draw from. Basically, I want a large library of content I can use to build my own pieces from. A toolbox with some of the gnarlier bits pre-made (no, I don't want to roll my own relational database, thank you very much) but not a pre-defined setting or hard (sub)genre limits.

But I know other people are in other places; this isn't a right/wrong thing or a better/worse thing, it's a way to try to explain differences in preference.

[KorvinStarmast]

In the middle are (in different locations) the various D&D's, which have implied world constraints and lots and lots of content, but which also have a framework on which the content is built and a strong tradition of homebrew at all levels.

I have run Empire of the Petal Throne and played in Chivalry and Sorcery games, which were two different approaches to what D&D started.
I think you'd like the former more than the latter, given that the world/setting is coherent and well ideated as "this is where you start, this strange, dangerous, and magical world.

Personally, I like a balance. I need the flexibility to come up with my own content (I dislike pre-written modules and being forced into someone else's setting as a DM) but I also want a broad palette of pre-generated things like stat blocks, spells, abilities, etc to draw from. Basically, I want a large library of content I can use to build my own pieces from. A toolbox with some of the gnarlier bits pre-made (no, I don't want to roll my own relational database, thank you very much) but not a pre-defined setting or hard (sub)genre limits.

But I know other people are in other places; this isn't a right/wrong thing or a better/worse thing, it's a way to try to explain differences in preference.

Tunnels and Trolls has evolved, over time, to have its own established setting and it has enough tools to tinker with.
I think that our group might enjoy it, but I don't have the system mastery to run it.
It's dice mechanics are, to say the least, unique.

[HidesHisEyes]

As I see it, a TTRPG "rule-set" consists of two pieces. The system and the content. One tells you how to resolve in-game actions; the other gives pieces of various size with which to play.

-snip-

Yeah that sounds pretty accurate to me.

I think there’s a sense in which you could argue a lot of games have a big overlap between system and content. Like the classes in D&D - they’re content because they tell you what types of adventurers exist in the implied setting, but they also form a pretty basic level of the gameplay experience. Like, one level above the core mechanics, if that makes sense.

I think there are also games that couple system and content together very closely but don’t end up relying on actual pre-written playable materials. Blades in the Dark is a good example: you have the city, the various factions in it, and procedures for navigating all that, but you still make your own scenarios. Sounds like you’d like it in fact.

[PhoenixPhyre]

Yeah that sounds pretty accurate to me.

I think there’s a sense in which you could argue a lot of games have a big overlap between system and content. Like the classes in D&D - they’re content because they tell you what types of adventurers exist in the implied setting, but they also form a pretty basic level of the gameplay experience. Like, one level above the core mechanics, if that makes sense.

I think there are also games that couple system and content together very closely but don’t end up relying on actual pre-written playable materials. Blades in the Dark is a good example: you have the city, the various factions in it, and procedures for navigating all that, but you still make your own scenarios. Sounds like you’d like it in fact.

Right. I'd say that classes are "core content"--the system side is "this game is class-based", but the classes define their own sub-systems within the greater system. Effectively, they're plugins onto the core game engine. In principle, you could take 5e D&D and rip out the current classes and replace them with different ones[2], leading to quite a different feel while keeping the core system the same. I say "in principle", because there are strong limits imposed by the base design patterns.

On the other hand, Blades in the Dark is an example of way too coupled system/content for me. It's not just scenarios that I want to have control over, it's worlds. My personal D&D setting is radically different in cosmology and underpinnings than the "stock" system, yet I can re-use most of the non-adventure content relatively straight[1]. If I were stuck in a fixed, known, locked-down setting coupled to mechanics that enforce that setting's constants, I think I'd go nuts. Or get bored. Because for me, most of the fun is in the exploration. In having the interaction of players and world tell me new things about the stuff I wrote. Those moments of "oh wow...if I take that idea they just mentioned and add it to that other thing, I get something that both answers questions I've had AND raises new interesting questions to answer." Like a good scientific theory, the best moments are those that both make predictions that work (in this case, are interesting to play in) and open new areas for discovery. A limited, fixed, known setting kinda puts a major crimp in that. Sure, it focuses much more at the person-level...but that's where my interest is weakest. I love playing at the setting/cosmology level. It's one reason why I consider myself a better DM than a player--I get bored dealing at the "one person" level for very long.

[1] although that's possibly changing with their new "shove the meta-setting into everything like it or not" and "being more opinionated about races and such" trends...[3]
[2] I know there's a FFXIV x 5e total replacement "mod" that basically does that, along with several other such ones. But I'd think that a no-magic, realistic modern-day game wouldn't go so well.
[3] yes, these footnotes are out of order. Deal.

[OldTrees1]

As I see it, a TTRPG "rule-set" consists of two pieces. The system and the content. One tells you how to resolve in-game actions; the other gives pieces of various size with which to play.

Yes.

Changing the system can spiral until one is better off creating or adopting a new system.
Changing the content is often more work but is mostly constructive instead of creative destruction.

I too like a balance. I want the system to be viable enough that I don't feel like changing systems. I want there to be enough content that I don't feel like I need to homebrew a splat book.

[PhoenixPhyre]

Yes.

Changing the system can spiral until one is better off creating or adopting a new system.
Changing the content is often more work but is mostly constructive instead of creative destruction.

I too like a balance. I want the system to be viable enough that I don't feel like changing systems. I want there to be enough content that I don't feel like I need to homebrew a splat book.

I think there are some systems that try to make it so creating content is trivial (so that the additional work of creating NPCs/setting pieces/etc is tiny compared to the necessary difficulty of coming up with a scenario), but I actually like coming up with homebrew to fit a particular need. As long as there's enough content existing to not have to for ordinary things. And for NPCs, especially, I like being able to take a stock one and tweak it to my needs without having to reinvent the wheel each time. That's one reason I'm not fond of "NPCs built like PCs" for anything that requires any significant effort to make a PC.

Basically, I want to have an optional library of pieces, plus the assurance that modding things won't shatter the system. Like Skyrim...without the inevitable swarm of Bethesda bugs.

[OldTrees1]

I think there are some systems that try to make it so creating content is trivial (so that the additional work of creating NPCs/setting pieces/etc is tiny compared to the necessary difficulty of coming up with a scenario), but I actually like coming up with homebrew to fit a particular need. As long as there's enough content existing to not have to for ordinary things. And for NPCs, especially, I like being able to take a stock one and tweak it to my needs without having to reinvent the wheel each time. That's one reason I'm not fond of "NPCs built like PCs" for anything that requires any significant effort to make a PC.

Basically, I want to have an optional library of pieces, plus the assurance that modding things won't shatter the system. Like Skyrim...without the inevitable swarm of Bethesda bugs.

Content includes things like PC classes and settings. While some (most) systems try to reduce unnecessary work (Ex: NPCs having easier generation rules) the process of making content will remain one that is simpler and more work in contrast to changes to the system. However they are not replacements for each other, so that information is really only useful to increase our appreciation when either is addressed, or to prepare ourselves when we need to address a gap.

That said it is nice that creating content, or tweaking systems, can be fun. They are just different types of mental/creative exercise. Like designing a card game vs making the first 200 cards.

[NichG]

If the distinction helps in design then that makes it meaningful.

That said, I most enjoy games which blur that distinction. Games where characters can e.g. invent new feats or spells or classes (inasmuch as the system has such things). Games where new and alien things come with their own dedicated subsystems which can be adopted or which might pose a challenge to overcome. Things which overturn expectations about the structure of things, and where that transformation can be intentional and fundamentally about events in the world.

So I'd say, sure, make the distinction where it helps organize information. At the same time, don't treat the distinction as good in of itself - it's a tool to be used when useful and put away when not.

[Zuras]

There can be a vast gulf between system and content. GURPS is a case in point, as you can adapt a wide variety of the setting books without ever using the base system. The generic, simulationist approach lets you translate a lot of setting specific bits to other systems fairly easily. Adapting setting material from less simulationist games is often much more work.

In particular, the time travel, parallel worlds and space settings books are all great if you want to run a more narrative game but also want to keep the crunchy bits consistent.

[Vahnavoi]

You are asking "is there a meaningful distinction to be made between a system and part of a system". On a general level, the answer is a trivial yes. The non-trivial parts are how adding or removing parts changes the system, and at which point it no longer makes sense to call it the same system. That has to be figured out by seeing how the part affects the whole, and sometimes the only way this can be done is testing the system.

[Telok]

Well, it depends.

GURPS, d6, and Hero are toolboxes. The rules don't make the content and the content doesn't mold or distort the rules. BRP, the system Call of Cthulhu runs on, is pretty close to that end of the spectrum. While people think of Champions when they think of the Hero system it also runs several variations from different hardnesses of sci-fi, spies & street vigilanties, and high & low fantasy (doesn't do horror real well in my opinion, but that's extremely subjective and it still does it without rules hacks). The different games don't alter the rules, they set limits & styles on how the rules are used.

Pendragon, Toon, Starfinder, and Amber are strongly tied to the content. The content shaped the rules and the rules are designed to support specific content. Pendragon simply doesn't do guns or high magic fantasy. You could force it to, but it would take a lot of forcing and homebrewing new rules to the point that it could be argued that it wasn't the Pendragon rules any more. Indeed it's been well argued that Pendragon doesn't even do justice to other versions of the Arthurian myth cycle.

Somewhere in the very soft & stretchy middle kilohectares are things like Palladium, Paranoia (some editions, others are up with Toon), D&D, M&M, Pathfinder, the White Wolf games, Warhammers, etc. Stuff like Palladium and M&M are more toward the toolbox end, but not quite there as there are areas they just don't do well in. It's not too bad to swap a character between the various Palladium games. The 2009 Paranoia edition could do fantasy with just some pallett swapping, although it would still be pretty humor oriented, and you could easily run a Star Trek or Star Wars game with it.

D&D, of course, is all over the place; AD&D could translate a character into Boot Hill (spaghetti westerns) and Gamma World, 3.x had the d20 stuff that... had mixed results, 4e didn't do anything but 4e though you could probably re-content it into assorted variations on squad combat tactics without much issue, 5e is adaptable to a variety of sword & magic fantasy genera without significant rules rewrites.

Yeah, I left out Fate, PbtA, Risus, etc., because I don't have enough experience with them to feel happy categorizing them.

[Lord Raziere]

Yeah, I left out Fate, PbtA, Risus, etc., because I don't have enough experience with them to feel happy categorizing them.

My experience is Fate far on the "System" end, but specific fate books that adapt the system focus on a certain setting tend to be more content oriented. sure Spirit of the Century, Dresden Files and Tian Xia are all the fate system, but each one has different stunts, modifications to the rules and such that aren't in Fate core.

while PbtA tends to be extremely content-oriented, as each book focuses on archetypes specific to the setting its built for.

I've looked at Risus once but forgot how it works.

But yes there is a meaningful distinction between content and system- I know from my experiences with Exalted and trying to replicate it in other systems. often you have to figure out how some abilities translate to another. especially when I'm trying to translate the weirdest most esoteric abilities of things like Sidereals, Infernals and Getimians.

[Satinavian]

I've heard that the culture of The Dark Eye (sorry, my german isn't good enough to get the real spelling) is extremely top-down content-driven--you're basically playing in fixed modules where you don't have much freedom to change things and there's a strong meta-plot. But that may be a wrong assumption.

TDE generally has the PCs not be real movers and shakers who can significantly change the setting and thus does not have to rely on fixed modules. But the metaplot-relevant ones generally are.

It also has at least 3 settings beside the main setting, each one far less restrictive and metaplot-driven. And for each one a quite significant portion of the rules get changed because system and setting is intertwined in TDE. Unfortunately none of the three got an English release.

[Glorthindel]

It would be intresting to compare games with baked-in setting against similar/identical games which are more open.

I believe Zweihander is basically WFRP with the setting and serial number filed off; I am a big fan of the latter, but never tried Zweihander, so I don't know if it still holds together once you have removed WFRP's default assumptions.

[Vahnavoi]

RISUS is a joke.

Slightly more elaborately, RISUS is a great example of a "rules light" game which works by having players hang arbitrary natural language descriptors on a skeleton of a simple dice game.

Of course, once you know how to look, many bigger budget complex games are constructed the same way, they just do more work for you.

Based on what I know of FATE, FATE's just a slightly more complex RISUS.

[Yora]

The mechanics of every system determine what actions are possible and what things are not possible. They also influence how difficult those things are and the odds to succeed. That has a great impact on what adventures are possible with the system, and also what kinds of settings can work with the system.

[Vahnavoi]

@Yora: that's the thing though, games like RISUS don't really do that before the players start adding in their own content, by which I mean, arbitrary natural language descriptors. Though I suppose a similar thing can be said of many considerably more complex games - the system actually pulling the game forward is the natural language spoken by the players.

[MoiMagnus]

I'd add a third point:

System / Content / Universe

If you rename the "spell fireball" into "grenade" while keeping the rules the same, you kept the System & Content the same while changing the Universe. Admittedly, some rules will look weird (sleeping makes new grenades spawn in your inventory), but RPGs are full of weird rules that you should not try to think too much about.

Conversely, if you slightly nerfed or buffed the fireball spell, you changed the Content while keeping the System & Universe the same.

Lastly, if you change the spellcasting rules to allow for simultaneous resolution of creature turns, you are changing the System while keeping the Content & Universe the same.

Different RPGs have different level of entanglement of those various points. While it's been a while I didn't open a D&D4e book so I'm not sure whether that was part of the rules or of our houserules, I remember that you could essentially rename all your magic powers to be whatever you want, and give custom description of them, as long as the technical effect was the same. In other words, the "Universe" was quite separated from the "Content".
On the other hand, rules about alignements in 3.5 (like Good/Evil tags on spells) means that the worldbuilding is necessarily linked to the System and the Content.

[KorvinStarmast]

rules about alignements in 3.5 (like Good/Evil tags on spells)

And as an aside, only made a clunky system (alignment) worse. Not every bit of tinkering represents an improvement.

[Zuras]

RISUS is a joke.

Slightly more elaborately, RISUS is a great example of a "rules light" game which works by having players hang arbitrary natural language descriptors on a skeleton of a simple dice game.

Of course, once you know how to look, many bigger budget complex games are constructed the same way, they just do more work for you.

Based on what I know of FATE, FATE's just a slightly more complex RISUS.

I’m not sure how that’s a substantive criticism of an RPG. Every RPG is a structure for combining group storytelling and some sort of conflict resolution system. Any system that facilitates the process by providing some structure is a legitimate RPG, assuming it succeeds in its own terms.

Never played RISUS, so I can’t speak to its specifics, but an RPG that reads more like an Improv facilitator’s handbook than a collection of crunchy bits is just as much an RPG.

[kyoryu]

I’m not sure how that’s a substantive criticism of an RPG. Every RPG is a structure for combining group storytelling and some sort of conflict resolution system. Any system that facilitates the process by providing some structure is a legitimate RPG, assuming it succeeds in its own terms.

Never played RISUS, so I can’t speak to its specifics, but an RPG that reads more like an Improv facilitator’s handbook than a collection of crunchy bits is just as much an RPG.

Well i think there is a distinction between games where the game rules act as an "engine" or framework/structure to play, and ones where they act more as a consultant, off-loading a lot of things like "can I do this" and the like to the table.

Like, if you throw a grenade, GURPS will tell you where the grenade lands with a precision of about 3 feet, how much damage it does to everything around it, etc. A game like Fate tells you pretty much "did you succeed" and putting some constraints on it, while leaving a lot of the details to GM/table consensus.

They're both RPGs, to be sure - I actually tend to prefer "consultant" games more, and find a lot of the criticism of them insulting and narrow-minded. But the difference is real.

[Vahnavoi]

@Zuras:

You really should at least read RlSUS wikipedia page if you want to understand what I said.

[Zuras]

Well i think there is a distinction between games where the game rules act as an "engine" or framework/structure to play, and ones where they act more as a consultant, off-loading a lot of things like "can I do this" and the like to the table.

Like, if you throw a grenade, GURPS will tell you where the grenade lands with a precision of about 3 feet, how much damage it does to everything around it, etc. A game like Fate tells you pretty much "did you succeed" and putting some constraints on it, while leaving a lot of the details to GM/table consensus.

They're both RPGs, to be sure - I actually tend to prefer "consultant" games more, and find a lot of the criticism of them insulting and narrow-minded. But the difference is real.

There’s certainly a distinction, but calling them a joke seems willfully blind to about half of what makes an RPG work. I’d consider it silly to charge people good money for basic advice for running meetings like “raise your hand to talk” and “don’t interrupt people when they’re talking” when you could buy Robert’s Rules of Order, but that doesn’t make those rules bad advice or a joke.

[kyoryu]

There’s certainly a distinction, but calling them a joke seems willfully blind to about half of what makes an RPG work. I’d consider it silly to charge people good money for basic advice for running meetings like “raise your hand to talk” and “don’t interrupt people when they’re talking” when you could buy Robert’s Rules of Order, but that doesn’t make those rules bad advice or a joke.

Yeah, I'm actually on your side on this.

[Zuras]

@Zuras:

You really should at least read RlSUS wikipedia page if you want to understand what I said.

You might want to make yourself more clear then, given you’re calling RISUS a joke and then likening other RPG systems to it. That came off as pejorative, regardless of the original designer’s intent.

If I liken another programming language to Malbolge, I wouldn’t expect a reader to interpret the comparison as positive, even though Olmstead wrote Malbolge as a joke.

[KorvinStarmast]

If I liken another programming language to Malbolge, I wouldn’t expect a reader to interpret the comparison as positive, even though Olmstead wrote Malbolge as a joke.

I guess that Windows 3.0 was Bill Gates' version of that. (I'll show myself out)

[Vahnavoi]

@Zuras: you seem to forget that jokes aren't supposed to be 1000% unambiguous and clear.

RISUS began as parody of GURPS, it's literally a joke system, and one of the punchlines is how it reveals how banally rules of bigger games are constructed. You may disagree, I don't care, your point that all roleplaying games combine "group storytelling with conflict resolution" doesn't really say anything to the contrary because it says nothing about quality of either.

[HidesHisEyes]

RISUS is a joke.

Slightly more elaborately, RISUS is a great example of a "rules light" game which works by having players hang arbitrary natural language descriptors on a skeleton of a simple dice game.

Of course, once you know how to look, many bigger budget complex games are constructed the same way, they just do more work for you.

Based on what I know of FATE, FATE's just a slightly more complex RISUS.

You might want to make yourself more clear then, given you’re calling RISUS a joke and then likening other RPG systems to it. That came off as pejorative, regardless of the original designer’s intent.

If I liken another programming language to Malbolge, I wouldn’t expect a reader to interpret the comparison as positive, even though Olmstead wrote Malbolge as a joke.

Wait, is the point that Risus was literally intended as some kind of parody RPG? Pretty sure that’s not true. I’ve read the game and a lot of 3rd party stuff around it and talked to the game’s author about it, and I’ve never seen anything to suggest that.

Vahnavoi can you elaborate more on what you mean? It sounds like you’re describing a game design phenomenon I’ve definitely seen - where the fiction is just arbitrary descriptors hung on the mechanics and it’s only the mechanics that really drive the game - but I don’t think Risus fits that bill at all. Have I misunderstood your point?

Back on the main topic of the thread, I do feel like system and content are sometimes much more tightly interwoven than we’ve acknowledged here. I was a bit surprised when OP suggested Blades in the Dark would be too far up that end of the spectrum for the OP’s taste, because it includes a map of its city and a list of factions and NPCs. I think another John Harper game, Lady Blackbird, literally tells you the scenario and has built-in player characters. Or Jason Statham’s Big Vacation, where the mechanics model going on holiday with Jason Statham, specifically. These are smaller, more obscure games not intended to be played for full length campaigns or used as a group’s go-to system, which is how they get away with it. But this end of the spectrum certainly exists.

[PhoenixPhyre]

Back on the main topic of the thread, I do feel like system and content are sometimes much more tightly interwoven than we’ve acknowledged here. I was a bit surprised when OP suggested Blades in the Dark would be too far up that end of the spectrum for the OP’s taste, because it includes a map of its city and a list of factions and NPCs. I think another John Harper game, Lady Blackbird, literally tells you the scenario and has built-in player characters. Or Jason Statham’s Big Vacation, where the mechanics model going on holiday with Jason Statham, specifically. These are smaller, more obscure games not intended to be played for full length campaigns or used as a group’s go-to system, which is how they get away with it. But this end of the spectrum certainly exists.

Let's put some markers on that particular spectrum (the coupling between system and content). Some will have examples, others won't:

0: The system does not provide any setting information at all. Or even genre. All you have is a set of abstract resolution mechanics. Probably also only works in very rules-light games. E.g. Roll for Shoes.

20: The system is modular, providing a core set of resolution mechanics and a feel, but having major chunks to give genre support provided by more specific "add on rules modules". Usually more a toolkit to build your own setting + system than a true out-of-the-box system (pending content). E.g. GURPS? Using a module does lock down the genre, but your selection of genres is huge and can be mixed and matched.

40: The system provides guidance on "conforming" settings and genres but does not require any specific one. Add-on content may provide settings, but DMs are expected to shape those to their likings. E.g. Most D&D & PF products.

50: The system provides a worked-out "hard default" setting with NPCs, maps, etc. Making your own is possible and doesn't break anything, but requires some work. E.g. Pathfinder. Starfinder

60: The system provides a worked-out setting with detailed NPCs, etc and sub-system mechanics are entangled with specific named entities from the setting (places, people, factions, etc). Using a new setting is highly difficult and requires edits in many places to existing "stock" mechanics. E.g. Blades in the Dark, from what I understand.

80: The system provides a set of concrete scenarios, but you can create your own characters. Creating your own scenarios is possible, but they must follow a set pattern for the mechanics to work.

100: The system provides a set of concrete scenarios that you can't easily deviate from, but character creation is possible within limits.

110: The system can only be used for one specific scenario with one specific set of characters and doesn't support any other without massive hacks. E.g Lady Blackbird, the Pathfinder board game (a stretch as far as "RPG" nature goes, but one I've played)

Uncategorized: The system doesn't provide a setting, but it does provide hard rules on genre and thematics, to which the mechanics are tightly coupled. E.g. Most individual PbtA games...I think? Playbooks are fixed and put hard constraints on the settings, but the system doesn't give you the setting details--instead that's generated by reference to the table's chosen ideas.

My personal preference for games is somewhere around the 20 mark. Because I love mucking around with settings at the core level. And systems that make that hard (by coupling mechanical details to the setting) get in the way of that fun. Even making my own scenarios in someone else's setting with the ability to tinker at the small scale (ie the 40-50ish range) is unsatisfying. And I'm not sure how to think about the one I've labeled "uncategorized". Is that high coupling? Low coupling? A spherical cow?

Edit: I think with this I'm assuming (possibly wrongly) that the flow goes System -> setting -> scenarios -> characters. That is, a system that dictates characters also must dictate scenarios and setting (to some degree). The idea of making "setting-free" characters or scenarios is alien to me. But I might be missing something that's obvious to other people.

Edit: Changed some of the values in the 20-50 range to better align with further discussion.

[HidesHisEyes]

Let's put some markers on that particular spectrum (the coupling between system and content). Some will have examples, others won't:
…

This seems about right, although I think I’d put D&D higher up, at least 5E in particular. To me the character classes - the presence of warlocks, paladins, druids etc - really strongly implies setting. And the differences between the classes and the experience of playing them is pretty close to the mechanical core of the game imo. They are mechanical objects but they are very much content at the same time.

Also, your mention of “conforming settings” is interesting. If I understand what you mean by that then I think it would probably be impossible to design a game at level 0 on your scale, as you described it. I suspect that if you set out to design a *completely* generic RPG, it will still lean towards certain genres, or not even genres but game feels, depending on your design choices. I might be wrong about this but my intuition is that even “roll a d20 and add a modifier” vs “roll a pool of d6 and add them up” is going to affect whether most groups want to use it for, say, light hearted anarchic games or more serious fare. I’m kind of out on a limb here, but I think Risus is a good example of game that aspires to level 0 and actually reaches level 4 or 5 on your scale.

Edit: I think with this I'm assuming (possibly wrongly) that the flow goes System -> setting -> scenarios -> characters. That is, a system that dictates characters also must dictate scenarios and setting (to some degree). The idea of making "setting-free" characters or scenarios is alien to me. But I might be missing something that's obvious to other people.

I think so…? Or I think the level of concreteness with which setting, scenario and characters are defined will usually match. Like, most PbtA games tell you enough about their setting that your take on it is going to fall within pretty clear limits, but it’s still a setting that you make. And then the playbooks don’t amount to full-on pregenerated characters, but they do have a lot to say about what kind of person the character is and their role in the narrative, not just their abilities. I actually think I’d put most PbtA games pretty straightforwardly in about the 70s on your scale. Blades is the 80s, Lady Blackbird getting close to 100 (and I’d cap it there).

EDIT: But a few seconds after posting that I’m already doubting most of what I said, lol. It’s an interesting way of thinking about games in any case.

EDIT 2 and then I promise I’ll stop: I would add two more terms into your flow so it goes:
System -> feel -> genre -> setting -> scenario -> characters.

Feel is sort of tone, atmosphere, vibes. Genre is genre of stories the game tells, defined fairly broadly.