That's not the twist guys.
It's pretty obvious from the beginning that the guests are in his mind, so that could even be called the main premise of the movie. Most definately not the twist.
shareMaybe the twist is that John is also imaginary... DUN DUN DUN that would be a cop out.
shareWhy would it be a cop-out?
Jeff Goldblum's TV series had a similar twist in the pilot - I didn't think it was a cop-out.
Maybe the twist has nothing to do with cops being out.
Or maybe there's just no twist - just a crazy guy tormenting a desperate criminal. No twist required.
And yes, I realize there are at least TWO actual twists not even hinted at in the trailer, but how nice would it be for a first-timer to think there are none, then be surprised anyway? I was surprised, right after the doorbell rang. It added a whole new, even less probable but forgivably ironic level to the story.