Another 2018 200-word RPG I thought was interesting was Can you hear me? by Eleanor Tursman. It has a mechanism where you add drops of color to water to make it harder to see through over the course of the game (drops of ink in the original). It seems like you could maybe do some interesting things with this, for example a token draw mechanic where it becomes harder over the course of the game to figure out which color token you're drawing from the colored water. It would probably take some physical experimentation to see what works and would be practical for actually playing.
An idea I've had that I don't think I would ever develop on my own is to combine the gradually color-changing water idea with melting ice: you make ice cubes out of intensely colored water, put the cubes into a container of clear water, and then as the ice melts the water gets progressively more tinted. I figure you would incorporate this with some sort of token-draw mechanic, where it's easy to tell the tokens apart through clear water and impossible to distinguish them in the fully tinted water, so it's easier to pick exactly the result you want in the early game but it becomes harder to pick the ones you want in the late game. (There might also be a painfulness tradeoff related to immersing your hand in ice water). I think the broad strokes of this idea are sound, but it would probably take some experimentation to figure out if it would actually work.
Since preparing the water/ice thing would be pretty elaborate to set up, it seems like it would make sense to make the game some sort of party game. Like Can you hear me?, I think the idea of the obscuring water being related to psychic visions makes sense. So my thought is that the game would be a "murder mystery party" kind of game, with the hook being that all of the guests are psychics and the way you have a "psychic vision" is to stick your arm into the slowly-obscuring water/ice container and draw something from the bottom.
Although I think this is an idea that could work it's not really the kind of game that I have any experience with, so I don't think I'd develop it on my own. If somebody who felt more confident about the party-game/LARPy elements was interested in pursuing this I might be open to collaborating (or if a group of people think it's a good idea feel free to run with it without me).