Game Storyline Ideas Horror/Survival/Puzzle

I have a gameplay idea where there are notes, with numbers on them, around the house that make up a code that you must enter into the main front door to escape while a “Demon Child” is lurking in your house, this is all inside a nighmare. However if im to put this on steam greenlight i need it so that its able to be played multiple times and is not the same game every time, like FNAF when you dont know when a animatronic is coming, so you dont just go to the front door with the same code ect ect and there not in the same place ect ect end of game in 30 seconds, guy wants money back senario if you get what im saying. Anyways i could change it so its the same concept but can be played infinatly with a differant play style? Sorry if i worded it wrong im speed typing cause im to busy to grammar check :confused: