I'm thinking about a small detective/horror game set in a quarantined town, where the player investigates a missing person.
The main gameplay would revolve around NPCs, investigation, information and a bit of immersive-sim design. The idea is inspired by Werewolf/Mafia, Prey, Call of Cthulhu, Pathologic and Shadows of Doubt.
There would be around 15–20 NPCs with personalities, routines, relationships, knowledge and secrets. The player would investigate by talking to people, observing their routines and gathering information.
For example, an NPC might claim they were home all night, but their routine suggests otherwise. You could confront them, investigate their house, ask someone else about them, or use another piece of information to expose the contradiction.
The immersive-sim aspect would come from having multiple ways to approach situations. If you need to enter a locked room, you might find a key, steal it, convince someone to let you in, follow someone inside, or find another way. NPCs would react to your actions and those reactions could affect later events.
There could also be a very basic combat system, mainly as a way to deal with problematic NPCs rather than as a combat-focused game.
I have a lot more in mind but i don't want to make post any longer.
The main thing I'm trying to validate is whether these mechanics are enough to carry an entire game. Does a game focused on NPCs, information, routines, investigation and player choice sound engaging enough?
I'm also unsure about how the NPCs should work.
Would it be better for their personalities to persist between playthroughs while their professions, relationships and roles change?
For example, Carlos could always be friendly but cowardly. In one playthrough he might be a hotel receptionist who knows something about a missing guest; in another, a police officer who knows something about the investigation.
Or would completely randomized personalities make the game more interesting and replayable?
I'd especially like to hear from people who enjoy detective games, immersive sims or horror.