Dementia rouge crawler.

You forget what you were even doing halfway in, your mind imagines a story and scenario and fills in gaps that were never there and sometimes are. The game is actually completely different and at the end it sees how far you strayed or how close you came to the reality of the story/situation.

I actually think AI will come in handy in this regard. Less typical than some RNG level generator but an actual voice in your head giving you a false narrative or direction
Weather it be fucking with the UI and making up objectives in text. To hiding items you swore you had in your inventory or when you backtrack to pick up an item you see that chasm that would normally be a platforming death is now an entire area that if you go down now gives you an entirely new direction becoming more distorted to where this quest in a fantasy setting has warped into a GTA setting along the way with your dementia actually making up the entire lore and reason for how and why so its not just
>RNG made new level
Player would have constant anxiety and paranoia cause you never know if you just strayed off.
That love interest NPC that had big tits and ass? Yeah you might have killed her when you swore you cleared a room but somehow an assassin enemy hits you from behind (actually it was just her trying to subdue you as she finally decided you needed to be subdued and get help and if that doesnt happen. We'll then your game mind will find other ways.

Youll snap to reality at times but you won't know it from your regular delusions. The most fun and exciting mechanics of the game also at the same time worsen the dementia, and if you abuse it to the extreme the damn controls and genre itself will be different. You wonder how the hell you ended up playing dance dance revolution in Tokyo that has a mirrored skyline of NYC replacing the blue sky when you started off the playthrough in a DnD like setting. And ofc in another playhtrough it could be a Medal of Honor to Danganronpa