I watched a Youtube video about switching from 5E to the OSR games and the differences between the philosophy between the two systems. It struck me how D&D 3 through 5 have moved dramatically away from internal mechanics, and leaned heavily on external mechanics. What am I talking about? Well, pull up a chair and let's think this through.
Mechanics = Game Mechanics
Obviously, when we talk about mechanics in the terms of games we are talking about game mechanics. The rules, how things work, what to roll and when to roll it, and how the rules shape the choices you make. We all know what these are so I am not going to explain the obvious. Next section!
Take a game like Monopoly, one of the quintessential board game experiences and a game that has a lot in common with OSR. The board can be seen as a dungeon, and while you don't roll for movement in the OSR, you do "land" on situations that require you to use internal mechanics to solve.
I land on a property. Do I buy or do we start an auction? Do I have enough resources and money? Am I saving for something a few spaces away that I really want? How would buying this help or hurt other players? Can I block a set by buying this? Is it useful for a trade?
You go through a lot of thoughts in your head when the game puts you in a chance situation, and while your success at your action is not guaranteed, you are heavily weighting risk versus reward against a pool of limited resources in your head for the entire game.
You are playing the game with internal mechanics - and while some choices may be influenced by game rules, the majority of them are not written down and you judging risk versus reward. Your game piece may have some special abilities as the game goes on, in Monopoly it is your cash and properties, in the OSR is is your cash and class. Everyone starts roughly equal, weak and powerless. Your power builds as you play the game. You can be put in an unwinnable position early, and come back out of nowhere if you keep playing.
Imagine a version of Monopoly with these rules (and I bet it exists or it has been house-ruled somewhere): the car rolls 3d6 for movement. The boot can kick a player off by 1d6 spaces when they land on them. The thimble pays half in taxes and fees. The hat gets $300 at "go" and so on.
Let's add feats and special ability cards the players can purchase for themselves when they land on the fictional "university" space. Let's give each game piece a list of powers they can have when they "level up." Let's give each property level and special powers when you invest in it! We need a 300 page rulebook for the Monopoly RPG now!
Okay, stop - it is fun to think of this as a thing and like anything Monopoly I bet it would sell well. But stop and think about your mental process when you would play this game, are the choices you are making when it is your turn mostly inside your head managing resources, or are they mostly navigating the rules and how you would get an advantage within them?
When a situation is presented to you, while resources management may play a factor in your decisions, a huge part of your decisions are now in a space inside the rulebook. You are not thinking internally but externally.
To be fair, the OSR has external mechanics in the ways things work, but like Monopoly, the mechanics are kept to a minimum and the classes are deliberately designed as "playing pieces." Your resources (hit points, spells, gear, and gold) are what you are managing and the primary driving force behind your decisions. In newer games, you are wondering if you should position your figure flanking to gain advantage, your character build, and all sorts of other "rules in the book" considerations before you are thinking about resources.
Are External Mechanics Bad?
Not really, if you enjoy navigating your way through rules and working up combos like a chart of fighters and combos in Street Fighter, hey, I am not one to say your fun is bad. There is a skill to working through the complexity and masses of rules, and designers sometimes put in less than optimal choices in order to create optimal ones. Your job is to figure out the puzzle and optimize.
My issue is when everyone knows the optimal path and one class build is all people play with when playing that class. Every character feels the same (until the next expansion), and the same powers and abilities are repeated at the table, over and over. You see a ranger come to your table, know their power rotations, and like clockwork, the player flips a switch and runs a script in combat. A, B, C, and D with you sometimes messing them up with an unexpected event.
This is just game design, and some games do it well, while others fail. Now games can fail for some and not for others, just like some movies are universally panned but become cult classics for a devoted fanbase. This is all personal preference, and what you enjoy is probably not the same as what I enjoy. But we are all gamers so it is good.
The Notion of a Game
We are getting deeper into psychology here and understanding the notion and concept of a game. A pretend activity where there are winners or losers. A set of rules, equally applied, and everyone is roughly equal to start. The power (or positions) of players change during the game. There are random factors introduced to simulate chaos - just like in life. The players' skills are important factors in success, but they do not solely determine who wins or loses (what the randomness is for, honestly).
Skilled players can deal with chaos better than unskilled ones, though at times unskilled ones may get lucky and succeed against a more skilled player.
OSR keeps to that core game design concept strongly, and there is a lot of resource management. Instead of picking up a "double shot ability" at 3rd level, you are thinking about how much weight your archer is carrying, how much they can haul out without getting weighted down, how many arrows they have left, and lots of other internal resource management factors that determine success.
Your resource management choices are the same ones everyone else follows, and these choices are the ones that help you mitigate chaos the best. The rules do not help you or protect you from chaos. They are merely there to lay out how your resources work, your gold, your hit points, and how your spell pool works if you have one. The external mechanics are mostly for resource management.
For me, resource management and playing that internal mind game is what I enjoy about gaming. Again, you may be different, and you know what - you probably are. I also found that the resource management skills these games taught me helped me greatly later in life. I am not gaming the system to get ahead. I work hard and I don't spend a lot of money. I can find pleasure in simple things, reading, writing, and making art, and don't need to feed myself a diet of expensive entertainment.
Gaming has made me a better and more successful person.
But back to games. A lot of your thinking with internal mechanics is done internally, what you have, what could happen, and how you are going to best deal with the possible situations that come up. In this way, the OSR is a lot like Monopoly, and in a way, also a lot like real life situations where we are trying to live life, spend our money wisely, pursue our goals and reams, and find comfort and security in a dangerous and chaotic world.