I had not seen the trailer and had absolutely no idea what the premise was. I can definitely imagine that it would be a more enjoyable experience this way, since I was surprised throughout. A fairly inventive movie, clever plot, and strong performances from the leads. The scares all add to the story, too! It's not purely jump scares for no reason.

EDIT: I just read the Trakt synopsis- it gives away a huge bit of the story. I am even more glad I knew nothing about this movie or I probably would have been more judgmental.

EDIT 2: Trakt has changed the synopsis to be more vague, but I still think I enjoyed the movie even more without reading anything about it or even seeing artwork. halfway through the movie I could not imagine how it could be a horror movie, which is exactly why it was such a good horror movie.