On the Flexibility of Games
I like to think about and explore systems, a part of me that mostly brings me pain likes to rank systems on which one is better, assuming they're comparable (like comparing 2 programming languages, not comparing a system of government and a way to put used dishes in the dishwasher).
Another thing that I like are games, playing them, reading about them, and thinking about them, and a first interpretation of games could be a system composed of rules and players. The question that remains then is, how good is that as a lens to analyze games with? I think a big part of that question rests on how flexible are the rules of a game, or rather how much can I change the rules of a game before we can't really say I'm playing that game anymore.
So let's think about how flexbible are games of different types, video games, board games, card games, and role-playing games.
Before that let me establish just some final ground rules (heh), Jay Dragon in Does Super Mario Bros. (1985) Have Rules? paraphrases the definitions of rules used in The Rule Book (2024) by Jaakko Stenros and Markus Montola as
- Formal Rules, which are what people point at and call “rules” in a board game or TTRPG. These include codified rules and also “house rules.”
- Social Rules, which govern how people treat each other and the culture of play that surrounds the game.
- Internal Rules, which are restrictions and goals people put on themselves, which they don’t need to vocalize to others.
- External Regulation, which are restrictions applied to the game by external pressure, like the law, the venue, or parents.
- Material Rules, which are the “brute facts” of the game, the materiality of the toys that compose it. These are “hardly rules at all” and, much like External Regulation, behave fundamentally differently than the first three kinds of rules.
Video Games
They're in some ways the most rigid of the mediums (some modders with deep computing knowledge can basically implement anything on top of another game, but that's a very specific case that I'll ignore). The peculiarity here is that in single-player video games you generally only have Material Rules: You can't do a grab attack in Mario, and I can't challenge an enemy to a dance battle in Skyrim. But since Material Rules are the hardest to change, this ends up meaning that video games are extremely rigid.
The closest example I can see of people "changing the rules" of a video game are the different allowed glitches in different categories of speedrunning, A Theory of Speedruns goes over that reasoning, but in some ways when you're speedrunning you're changing the Internal Rules (I'm playing as a hero and I will help people in need, instead of killing them to get xp quicker and finish the game faster), if you're using glitches you're arguably changing the Material Rules, and if you're speedrunning specific categories then we end up with specific External Regulations added on top of the way you play the game.
Board Games
Board games on the other hand are very oriented towards Formal Rules, which are supposed to be thought to you through the game's rule book. This gives us significantly more flexibility in board games, sometimes one could even say too much! I've seen many people recommending others play the digital version of Root so you can better internalize the rules of the game (because in the computer version of the game the Formal Rules become Material Rules!), and people cite multiple statistics on how few players correctly play a given board game for the first time.
Besides outright errors we have the notion of house rules, where a given group of people play with rules that don't match exactly what's written in the rule book, this could be because one didn't have a written manual (think chess in the middle ages, or buying a second-hand game pre-internet), or because people just decided they'd rather change the game a bit to make it more fun/interesting.
Just to be clear, we keep Material Rules as strong manacles on board games through the components, tactility is quite important in board games, and so making new rules that would require pieces that we don't possess generally isn't done.
Card Games
Card games, because we generally assume one should need only a deck of cards to play them, with few exceptions, end up with fewer Material Rules than board games. Not only that, but for card games like Magic the Gathering (TCGs?CCGs? Unclear what term to use) you have that the text on the card subsumes any pre-existing Formal Rules of the game. Not only that, but in these games one can overlay rules about how one deck is constructed (minimum number of cards, number of copies, which sets the cards can come from, whether one pre-constructs the deck before playing or we'll be drafting the cards from a pool before playing), how many players are playing, whether we have teams or not, and so on. These rules can vary from Formal, to Social, and sometimes also Internal. But by overlayig these rules it also means we can change the rules and jump from a form of play to another by changing them, meaning that now we have even more flexbility than we had before! To make this example more concrete, check out how many Magic the Gathering formats are listed on Wikipedia, and compare with how many different ways do you play any of the board games you know.
Role-playing Games
Now we reach what must be the apex of flexibility, RPGs have very little Material Rules, the majority requiring just a randomiser like dice and cards, everything else is happening in the minds/imagination of the players. And so effectively all rules in RPGs can be changed, you can change how initiative works, whether checks are binary or have graded results depending on how close the result is to the success threshold, how persuasion works, whether spells require materials or not and so on.
The consequence of this is that it's extremely hard to talk about the game system part of an RPG, because it's so easy to change it, and there are so many changeable things, that one be using only 10% of the original rules of a game and 90% of things they created on the table and still say they're playing DnD (er, I mean playing the original game).
On the flip side it also means that analysing RPGs and creating material for them is very nuanced, an RPG isn't just the formal rules, but it's also the setting, it's the stories the players are expecting to be part of, it's the tone of the table, which is often affected by the implied tone of the book. One can write a bestiary full of stats for every monster you'll face, or one can write a bestiary that just invokes the right feelings and plants the seeds of the stories you'll tell.