Continuity mistake: At breakfast, Robert's monitor is behind his right shoulder until Paul comes to visit and then the monitor is on the other side of the bed (behind Robert's left shoulder). (00:25:10)
Continuity mistake: In the bar scene after Padraic tries the "new tactic" on Colm, in some shots of the scene you can see 4 pint glasses on the table (three empty and one full for Colm), and in other shots there are 5 (three empty, one full and one half full). (01:20:47)
Continuity mistake: The handcuff around Ava's right wrist looks loose enough for her to free herself simply by pulling her hand through it. In a later shot, the handcuff is closed almost against her skin. (00:54:30 - 01:00:39)
Continuity mistake: The view from the (unseen) car driving toward the distant house on a hill showed fog well above the pine trees, but when the car/limo got to the house/mansion (10 seconds later), there was no fog. (00:02:17)
Continuity mistake: The wall clock, after staying at around 10:12, jumps 4 minutes (to 10:16) in less than 20 seconds. (00:01:05)
Continuity mistake: Inside the building, Nina is at different distances from the man on the bench, ranging from about one body's width to a few widths away (while accounting for her limited movement). (00:15:15)