Yeah, This is Confusing, actually i had been doing the game for years as some people know since the old gamepage, all about this demo content is just The First 3 Nights of The Main Game with the Final Game UI and Stuff like Cat's Mechanic Update

Remember that this Game is a sequel, it would be confusing to new people who doesn't even know what is going on, but no worries about it, just Enjoy the Game :D