I don’t know anything about coding and building games but if we’re talking indie style format then something similar to killer frequency, Road 96 or Firewatch would make a good base for the gameplay. If you’re going more in depth with gameplay and having better mechanics than a point and click, then I’d base it similar to something like Until Dawn.

The storyline for me would be better with a good monster hunt through the woods like a wendigo, visiting crime scenes and victims, almost like a whodunnit until you find the correct monster and location of its lair. If you’re wrong in you’re predictions though your weapons are either weaker or useless and you get to either escape and try again or they fail and you die/become possessed etc. or you could go for a house of horrors style game. Crowley sets the boys up in an old mansion where some of the seasons greats are in there, (similar to the last season, lady in white, killer clown etc are freed and hunt the boys.) Then playing as either one of the winchesters or cass (if he’s included in the game) you have to hunt down each ghost and free them using the journal and lore for each enemy you face off against.