One of my personal game design white whales is an OSR game that takes the modern roguelike "core advancement schema is constrained to single runs, plus some sort of auxiliary metaprogression based on rewards for completing runs" and cross-breeds it with the "dungeons are mythic underworlds/fragments of other worlds/living creatures parasitising our reality" conceit that some contemporary OSR games go for to produce a game where the core rules furnish robust character creation procedures but simply have no concept of advancement, incremental or otherwise, and then each individual adventure module has its own context-specific advancement schema which is only effective inside that particular dungeon, and goes away outside of it.
e.g., one dungeon might allow characters to advance by progressively enbodying mythic archetypes to produce something resembling a conventional class-and-level system, save that the "character classes" are specific to that dungeon, and a different dungeon which nominally has the same advancement schema would have a totally different set of playbooks; another might have fully randomised advancement in which player characters acquire weird body-horror mutations that grant mildly game-breaking super powers with no ability to influence which ones they get; and a third might have wholly extrinsic advancement based on acquiring golf-bags full of magic items with oddly specific functions. In each case, progression through the relevant advancement schema would be extremely rapid, such that exploring its full gamut in the span of a single adventure module is feasible, and player characters would "reset to level 1" once that module is complete.
However – and this is the keystone of the entire exercise – we're explicitly not obliging GMs to basically design a whole new game every time they want to roll their own adventure module, because 90% of the text would consist of a long list of modular pieces of advancement schemas which can be plugged together like Lego bricks to produce whatever the dungeon at hand uses, tied together with some sort of monstrous set of Big Stupid Tables which enable advancement schemas to be randomly generated, with the GM's only obligatory responsibility being to invent an aesthetic for the dungeon which justifies these particular elements coming together in this particular configuration.
To pose a particularly silly example, imagine rolling up a new dungeon and getting the schema elements "randomised, non-hierarchical upgrades", "upgrades are intrinsic modifications to the affected character's mind, body, or soul", and "each upgrade is a self-willed NPC and accessing its advanced functions requires persuasion, negotiation, and/or bribery". Is it a biopunk dungeon where characters advance by acquiring talkative parasites with incongruous goofy accents? Is it like a Disco Elysium thing where you advance by learning skills, but the skills are alive? Do you have ghosts in your blood?
Thinking about the kinds of characters who would do that for a living is extremely fun.
The core book's character creation chapter would of course include a Big Stupid Table of potential explanations for why you're doing this to yourself.
@evilweirdo replied:
The cheap lethality of some of these games would absolutely work better in a roguelite kinda thing
Dungeon where the only advancement trigger is "dying".
