The Dr. Fletcher character is said to be a psychiatrist, which would mean she has a medical degree, not just a master's in counseling. A person with a masters degree is not referred to as Dr.
Casey is shown having been trained since she was a toddler to use firearms, yet when she does use a shotgun, she racks and fires on an empty chamber, even though she's shown looking at and then loading her last two shells.
When Dennis is in the train station after Patricia has bought flowers to lay on the train platform, an extra who is walking behind Kevin can be seen looking directly at the camera.
When Dr. Fletcher receives the first email from Kevin, the subject reads "We need you;" however, when she opens the email, it says "No subject" in the subject line.
When Hedwig finishes his dance for Casey, he switches off his CD player which causes it to open. In the next shot it is closed.
At the end of the movie, Casey's makeup and hair are perfect despite being held hostage, running around in the filthy maintenance basement and fighting with the beast.
When "Dennis" brings the girls' sandwiches, you see Marcia pick up half of the sandwich and take a bite, but as he leads the girls to the kitchen, the sandwiches on both plates are shown uncut (whole) and there are no bites.
Kevin is counted as one of the 23 personalities inhabiting Crumb's body as shown by the video logs on his computer. Dr. Fletcher is emailed 20 times by him to warn her about the Beast, which suggests 20 of the 23 personalities emailed her. As Dennis, Patricia and Hedwig are the personalities who want to welcome the Beast, it is believed none of them emailed Dr. Fletcher, which accounts for the three missing personalities. And since Kevin is one of the 23 personalities, it would suggest he is one of the personalities who emailed her. However, when Casey states Kevin's full name to bring him "into the light", he reveals he has no memory of any event since September 2014, which shows that he hasn't "taken the light" for two years, so he could not have emailed Dr. Fletcher.
When Dr. Fletcher interviews Barry about the incident that happened at his work, we see her without glasses. In the next shot (from behind Dr. Fletcher) we see her remove her glasses.
When the girls attempt to escape the first time and Claire runs down the corridor, you can see the camera/production equipment casting a shadow on her.
When the camera approaches the father putting food in the trunk, you can see the camera crews legs in the reflection in the fender of the car.
There will be no alarm if you open a passenger door of a car with the keys in the keyhole. Alarm will sound only for the driver's door.
When she is loading the shotgun, it breaks over and loads from the breech. This makes it a single shot, but later on she is holding the gun and cocks it by pumping it. A breech loader only has capacity of one shell per barrel.
When Dr. Fletcher is giving her speech through Skype, you can see her being projected onto the large screen for the audience. The video on that screen is completely synchronized with the small image on the bottom right, but it should be delayed, as the video signal has to first travel there, be projected on the large screen, recorded by the second camera and finally sent back to her computer. Note: If the internet speed is not an issue, it doesn't matter how many feeds its going through, it still travels at the speed of light and one would not notice any delay. Live TV shows have added a delay only due to the Janet Jackson incident at the Super Bowl.
Immediately before Dennis knocks out Claire and Marcia in Mr. Benoit's car he locks all the car doors, but a moment later, Casey opens the passenger side door, which is clearly shown to be unlocked.
In the close-up shot of Dr. Fletcher's degree scroll from Tulane University, the school of political sciences is misspelled as "political scineces". In addition, her degree of Master of Psychology would not be awarded by a school of political sciences.
When the Beast comes up from behind and grabs Dr. Fletcher, her glasses are present just above his arms. The subsequent shots when the Beast continually increases pressure, her glasses are no longer there.