I've had an idea for an RPG where the story is very Truman Show-esque. Where if you play it "normally" it guides you along a pretty traditional JRPG quest of linear story, with your standard diverse roster of allies, who travel about the world going from town to town and dungeon to dungeon, to fight your 2-dimensionally evil final boss and live happily ever after with your shallow designated romantic interest.
For astute players however who pick up on the seams of the world and the storytelling, the players can go against the intended path and objectives, and slowly learn that the entire quest is a sham, all your allies/NPC's/Enemies are actors, the world you live in is an elaborate cage to keep you living out an idle and meaningless fantasy for all eternity over and over. Of course, this would be fairly difficult, as not only would the clues be hidden and benign enough that experienced players would brush them off as 'accepted cliches' that come with the territory of game playing; but also that the quest would be very robust against your attempts to break it. If you try to sequence break, the story changes to accommodate it, if you interrogate your "allies" they play dumb and persist in maintaining the illusion at all costs, and it's only when you can really prove beyond doubt that the world and your quest is fake does it start to crumble, it rapidly unravels and the entire world at once becomes hostile, having failed to keep you sedated and therefore has to try to eliminate you to keep you from escaping your 'cage'.
The entire idea is very Matrix-like in that regard. I don't know if there's any game like that already in existence, it sounds like something that would be very "woke" and therefore something an indie would atleast have tried with a low budget game. What I have imagined though isn't something I've ever stumbled across though.
Back about 15 years ago I used to hang around on the RPGmaker forums and weirdly, someone actually made pretty much
exactly what you're describing!! I can't remember the name, or much about it at all but you were basically on a typical 'save the world' quest and as you got further and further through the game you started noticing random bits that weren't right. In one of the few bits I remember, an NPC mentioned something in a quest before you did it, and when you brought it up in conversation none of the people on your team could remember it and kept changing the subject.
Pretty terrible game action wise, but it was a sort of minor hit in the community due to how creepy it was. Even with the terrible stock top-down graphics it still managed to make you feel really, really alone in a way that few games manage.