The main protagonist is shown in a flashback to have been sexually assaulted by her father as a child during an eclipse. The father masturbates with her on his lap. He is later shown manipulating her into not telling anyone what happened to her. It is implied that he may have assaulted her again.
The couple plays a BDSM game where Jessie is handcuffed to a bed and Gerald sexually dominates her. She expresses discomfort a few moments in, but Gerald ignores her and continues. After further protest, Gerald stops, but verbally belittles her. In a flashback scene later in the film, 12-year old Jessie sits on her fathers lap while he masturbates (not assault strictly speaking, but certainly sexual abuse).
SPOILER Near the end of the film the "moonlight man" is revealed to be a mentally ill disabled man whose criminal graverobbing escalates to assault and murder.
At first I while I was watching this I thought the other commenter was blowing things out of proportion, but no. Suddenly the scary lurking monster is a real person with a real disability (the actor has Acromegaly). There’s no reason for this. He could have been a real person without a disability and when she confronted him in the court room the fact that he wasn’t as scary as she’d thought would have worked well with the parallels the movie was getting at. Instead we get yet another disabled person demonized in a horror movie.
The couple builds up to having sex but does not follow through. Discussions of sex. Middle of the movie as well, see "sexual assault" answer. (rephrasing because other comment had spoilers)
Theres a scene where Jesse has a flashback to when she was sitting on her fathers lap while he masturbated. He later manipulates her into not telling anyone.
Toward the end of the film, the main protagonist escapes and drives away in her car. She has trouble staying conscious during the drive and veers off the side of the road but is able to continue driving. Eventually she crashes the car and is visibly injured by the impact (blood comes from her mouth and nose). The sound of the crash alerts people living nearby who come and help her.
One of the protagonists in the film dies suddenly, and his body is eaten by a dog throughout the film. You can see the dog walking away with bits of flesh in his mouth. Blood pools on the floor from the death and is spread in footprints by the dog and another character.
Toward the end of the film, shown in a flashback, the protagonist anxiously squeezes a glass and causes it to shatter in her hand. It bleeds and she is bandaged.
The most graphic scene is where the protagonist again shatters a glass to cut her own hand and wrist but this time purposely. She uses a shard of the glass to slit her wrist in order to slick her hand with blood so that she may slip out of the handcuffs. She is shown doing this action a few times. As she pulls her hand out of the handcuffs, her hand partially degloves and the skin separates from it showing the tissue underneath. It is shown briefly but graphically, and again in glimpses until she eventually uses pads to bandage her hand. She falls unconscious and wakes up with the pads soaked with blood.
The partially eaten and decomposed body of another character is shown briefly.
The protagonist crashes a car and is shown with blood coming from her nose and mouth.