Continuity mistake: Kiril comes out of the restaurant's back door, shouts at the dog and puts a hand on Nikolai's shoulder. He is talking across the two shots about his wife, in the second one his hand is not on his shoulder, it is on his back. (00:07:15)
Continuity mistake: Anna's uncle storms away refusing to translate the notebook of the dead girl. Anna sits down while her mom lays the table. In the close-up, she has all the utensils on the cloth (she missed the spoon in the wider shot) and the knife shifted more to her right. (00:06:35)
Continuity mistake: The corpse is examined by the police; the corpse is shown once in its entirety. The knee is exposed. When Donald Sumpter inspects the body, he has to roll up the pants for the knee to be visible. (00:29:20)
Continuity mistake: During the kiss and farewell with Nikolai, Naomi Watts' hair is all agitated by the wind in every shot from one particular angle (camera behind his shoulder), and goes back to being unperturbed at the cut. (01:32:55)
Continuity mistake: Kiril and Nikolai hug in the wine cellar. There's a constant back and forth between two angles where Vincent Cassel's hand is positioned differently, either on Mortensen's back, or shoulder. (01:08:40)
Continuity mistake: Anna brings Semyon only copies of the original diary. The sheets are held together by handbag clips, which are closed in the close-ups, and open in the views from her angle. (00:23:00)
Continuity mistake: Looking at the security monitor as he talks to the young Maria, Kiril has a balloon between his hands that is balanced differently between shots. (01:26:40)
Continuity mistake: The necklace worn by Vincent Cassel changes position on his chest during the cut when Nikolai tells him "Calm down, Kiril." (00:34:05)
Continuity mistake: Anna walks up to Uncle Stepan holding a glass. She holds it with just her left hand in the wider shot, becoming two in the following, across the sentence "You have an uncle, Anna, who doesn't steal things from the dead." (00:06:00)
Continuity mistake: At papa's personal brothel, Kiril cups Nikolai's chin telling him how he wants to make sure he's "no queer." When Cassel is from the front, he's pointing his index finger under Nikolair's chin, while in the front views of Viggo Mortensen's face, Cassel gets awfully creative with the appraisal of his buddy's manliness, doing things like thumbing the cleft of his chin or using his ring finger instead. (00:34:45)
Continuity mistake: When Anna handles the diary of Tatiana over to Nikolai at the fast food restaurant, Nikolai's right hand does not have the big tattoo.
Suggested correction: I don't think I can confirm this mistake. The hand that takes the diary in close-up is the left one, and when he uses the right hand, the tattoo is there. It's a faded tat to begin with, so if the streaming quality when you watched it was not optimal, it may be a detail easy to miss or that blurs out with compression noise. But it is there.
