The Guest

When David and Anna are at the Halloween party a guest can be seen wearing the Fox mask worn by one of the home invaders in Adam Wingard and Simon Barrett's previous feature: You're Next (2011). The party guest is played by Steve Moore, who composed the score for the film.

Note how in most of his close-ups Dan Stevens doesn't blink. This is to emphasize the strange, unsettling aspect of "David".

Steve Moore, who composed the score for the movie, used the same type of synthesizers that John Carpenter and Alan Howarth used for composing the score of Halloween III: Season of the Witch (1982).

Dan Stevens was completely emaciated when he first met with film-makers Adam Wingard and Simon Barrett because he had lost 30 pounds to star in A Walk Among the Tombstones (2014). They really wanted him for the role but were worried about his appearance because they wanted a really buff soldier physique for the lead character. Wingard said that Stevens looked like Christian Bale in The Machinist (2004) but they wanted him to look like Christian Bale in Batman Begins (2005). However, they gave him the role after Stevens promised that he would workout like mad and bulk up for the role. The day he was cast, he was assigned personal trainers and dietitians to begin his physical transformation for the role. He worked out daily for 2 hours a day, even during shooting eventually putting on 25 pounds of muscle and building six pack abs for his shirtless scene. The scene was scheduled in the last week of principal photography so that he got as much time as possible to build up his physique. He was cast just a month before principal photography began and the shoot was two months long giving him about 3 months to prepare for his the scene. Stevens said that it was the first time in his career that he had done serious body-building for a role and he was thrilled by the aesthetic appearance of his body in this film. He said it also allowed him to break his former image as a chubby & restrained English gent on Downton Abbey (2010) and surprise audiences by crafting an image of a shirtless macho soldier. Wingard pointed out that Stevens' body shape significantly changes from scene to scene. This is because the film was shot out of sequence and Stevens was still training throughout the shoot, so that he appeared frail in some scenes and very muscular in others. Wingard and Barrett said that Stevens' shirtless scene was one of the most important scenes in the movie because they knew it was going to be a major selling point and a sure-fire trailer shot and they spent more time shooting this scene than any other. Wingard said that he "wanted to sexually objectify and fetishize Dan Stevens' shirtless body in this shot as it went with the playful nature of the movie where the audience was subversively being asked to ogle at body of the bad boy character. The film-makers scheduled that scene as late as possible because they wanted Stevens' body in "optimum condition". In preparation for that scene, Stevens shaved his chest and tanned his body so that all his muscle definition could be seen. In addition, Wingard said that to deepen the muscle definition even further, the trainers had Stevens do a trick where "he did not consume any food or water for a day, and then just before the shot, he drank a diet coke and did 100 push-ups and 100 sit-ups". This tightened up his muscles and made his veins stand out giving him the super-ripped appearance that the film-makers wanted. The shot was then subsequently used in all the trailers and publicity materials for the film.

The film is intentionally structured as a horror film with the pace of a thriller.