I don’t really have one big idea that has all the information you want but I have two smaller concepts.

A paranormal game based on movies like Poltergeist or The Conjuring in which the main characters have to deal with ghosts trying to kill them. This may be a bit of a far reach and something that may be impossible to implement but I would like for them to add a gameplay mechanic in which some characters will be able to get possessed and then your gameplay options will change For example, you reach a point where you have to choose a dialogue option but the options for a possessed character are much more hostile towards the other characters.

And my other idea is a game based on classic stereotypical slasher movies. All 5 characters are based on stereotypes of old slasher movies: The douchebag jock The dumb blond who is fucking the jock The final girl The final girls best friend who is really smart and a potential love interest for her The creepy neighbor who all the other characters think is the killer but actually isn’t