If you want fans to like your horror movie, do one thing: deliver on your promise. The genre has always operated that way. If you show a guy in a hockey mask on the poster holding a machete and menacing teenage girls in bikinis, that must happen in the movie. It’s not the same for drama or action films. A Jason Statham cardboard theater-lobby display that depicts him holding a semi-automatic is not a promise. It’s an obligation.