I've had an autistic horror mod idea for the longest time.
>Set at nighttime, with much darker lighting and ambient lights turned way down
>forced first person perspective
>no pedestrians at all
>completely silent, save for your own footsteps, breathing, car sfx and subtle nighttime ambience
>have to find a few grafitti spots around the entire map (with hints, of course) to tag
>a single random npc in a vehicle patrolling the entire map to hunt you down, with more aggressive pathfinding the more graffitis you tag
>you are never given any clue as to where this NPC could be at any moment - could be across the entire map, to maybe the next street over
>more realistic vehicle handling to make car chases feel more daunting
>scary ass music kicks in whenever this npc gets close, CJ starts freaking the fuck out