Some attempts at answers for Kazumi Chin (@kazumiochin):

Is playing tic tac toe slash increasingly complex non narrative games world as earth?

I'm going to make the strong claim here, because that's my way; I still think the weaker versions of the argument probably carry weight.

Tic Tac Toe does qualify for this World-as-Earth business, though probably not in a compelling way. This is the ontological situation that allows for play to have rhetorical content, but it doesn't guarantee that that content will be potent or anything. Tic Tac Toe probably doesn't have as much to say about the human condition as D&D does. But it probably says something, and even if it doesn't, that doesn't exclude it from the ontological possibility.

I actually arrived at this conception by thinking about non-narrative strategy games (not TTRPGs, initially). There's a procedural rhetoric to these things (Persuasive Games, Bogost, 2007), but I was unsatisfied with both the metaphysical and practical dimensions outlined (or not) in that book. So this Heidegger stuff is the metaphysical part; the practical part is Virtue Theory, which I haven't gotten to yet.

Is a tournament which is a set of rules itself a world as earth; a martial arts tournament for example, is that art? A tic tac toe tournament? does it need to be sufficiently complex?

A tournament is a kind of meta-structure that can qualify itself as a game (maybe it must be a game), and can therefore set up the World-as-Earth dynamic. Or at least has the ability to confer game-ness onto some endeavor.

A martial arts tournament seems completely indistinguishable from, say, a Magic: the Gathering tournament, to me. There is a game of martial arts, separate from the practice of using it to actually fight “enemies,” that has rules and structures and such. I imagine there are rules against snapping your opponent's neck in tournament play, for example, which distinguishes it from non-play fighting (I'm not willing to fully exclude non-game fighting from game-ness, but I'm also not ready to defend it, as yet). And there is some relatively complex rhetorical content to a martial arts tournament, for instance with regard to violence and its place in the world and in our lives. This rhetorical content resides not merely in the discourse surrounding the game among participants, but in the structure of play itself. The discourse, I argue, is to some huge degree determined by the structure of play; they inform each other. And yes, that gives it the same capacity for being art that other forms of play have.

Increased complexity seems to correspond to increased capacity for rhetorical content, and for art. So Tic Tac Toe's simplicity sharply limits its ability to make arguments, and to be art.

If the game play is art but the rules themselves are not, does that mean that for example blood piece in my Twitter banner is not art until someone plays it? What does it mean to play it then? Can I think about it? Is that sufficiently playing? What is the threshold of play?

And if a set of instructions is not art until it becomes a world, then is a poem not art until it is read? And only in the reading? So what’s the point of making the distinction? Isn’t it always true art is only art in the instance of engagement?

I would not make the argument play is art while rules are not. I might make the argument that engaging with art is when it comes into “fullness of being” or whatever, but then art is always-already engaged with—by the artist, if by no one else. The creative process is play, and play is a creative process.

Now as far as the audience goes: is the act of reading/thinking about rules a creative act? This seems nearly identical to the question of whether reading a stageplay is a “valid artistic experience” of the play, as opposed to seeing it performed, or performing it yourself. And I think it's fairly straightforward to say yes: the work of art is polyvalent in form, and therefore too in experience.

This is all just normal old context: I read a game, I imagine it, I play it. I read a stageplay, I imagine it, I watch it, I perform it. I have a cold, I'm drunk, I'm 31 years old. All of these things affect and inform our interaction with the art, but none of them change the essential nature of our interaction.

So for games, which set up the World-as-Earth dynamic, it might be useful to construe these contextual elements of our interaction with the game as an Earth that we bring to it, in addition to the World-as-Earth the game sets up. That's not something I've spent a lot of time unpacking, but it seems worth thinking about.