Roughly 12 years ago, I posted this Youtube video about a fascinatingly broken Minecraft world sent to me by an acquaintance:
Said acquaintance was modifying Minecraft's world-gen to try to add more prefab buildings into the village generator, and to test that it was working, increased the generation rate of villages... well past the recommended maximum. The result was a world I wound up calling "Euclidville," in which a gigantic, solid cube of world is inhabited by thousands of buildings attempting to generate inside of each other. Contrary to most generated Minecraft worlds, in Euclidville, the ongoing struggle is not building shelter for protection from the outside. The entire cube is, technically, shelter, but it is dark enough in most sections that monsters may very well be spawning inside of it. The player does not struggle to find coal to make torches, as the torches largely already exist and just need to be plucked from their improper hangings and street-lights shoved into closets and jammed through several ceilings.
I feel like this would be a killer concept for a proper game. The kind of liminal-space horror provided by your average "Backrooms" implementation (or games like Exit 8), except that the threat is not necessarily some intangible horror (or cheap jumpscare), but running out of food or being exposed. Rather than wander endless, featureless liminal hallways, the hallways would be crunched and crammed into each other, and the player's struggle would be to neaten things up by dismantling wrongly placed walls, floors, ceilings, and furniture to use for other purposes.
What's the goal? Presumably you're trying to get these buildings back into some semblance of functionality with a rudimentary set of construction tools. You're taking apart what is technically supposed to be five buildings that all happened to exist in the same one building worth of real estate. What's the threat? To be honest, I'd have no real idea. The existing Minecraft mobs are mostly played out at this point, and I'm unsure that anything like them would really be all that interesting in this kind of setting. I feel like our threat needs to be intangible, and not something that just kills the player. The "exposure" stat, then.
I'm kind of inventing this off the cuff so I have no idea how well it'll work as a game mechanic, but here's the brief: "Exposure" is a meter (it doesn't have to be visible to the player) that quietly, slowly ticks up whenever the player is in a room that they have not "finished" (i.e. walls fully closed, well lit, has a place to sit or rest and is free of any anomalous structures), and ticks up faster the farther the player is from a finished room. if exposure gets particularly high, the player's vision (or nearby structures/furniture?) begins to distort. if it maxes out, it becomes impossible to see for a short while until exposure suddenly resets to zero, but the player is randomly warped to an unfinished part of the building. reducing exposure means staying close to finished rooms and resting whenever possible.
Idea's free to a good home; I lay no claim to it. Maybe gimme a shout if you make this into something real.
