Continuity mistake: After Johnny learns of his last rescue's death, when he enters the hallway the treatment room beside the nurses' station is treatment 4, but when Brackett and Early pass the nurses' station to go save a rabbit from a sousaphone, it's treatment 2 that's beside the nurses' station. Then, as soon as Brackett and Early enter their door, in the next shot as Dix speaks to the officer, it's treatment 5 beside the nurses' station.
Visible crew/equipment: In the scene where Prue comes home and finds Andy inside the manor. There is a shot where if you look behind Andy's shoulder you can see half of the body of the director in the background in the observatory room sitting in a director's chair. (00:16:00)
Other mistake: During the scene in the banquet hall, as Tormund says "most people get bloody murdered, they stay that way", look at Daenerys in the background - a disposable coffee cup is on the table in front of her. This brown cup with a white plastic lid is nothing remotely like the style of cups they're all drinking from in the scene. HBO acknowledged the slip up and digitally edited it out on streaming services, reruns and future DVD releases.
Continuity mistake: When Ryan is lighting Marissa's cigarette with his, at the start of the shot it's full, then the shot goes to Ryan and it's still full. But then the shot goes to Marissa and if you look at Ryan's cigarette you can see it is almost all gone. Then the shot goes to Ryan and the cigarette is full again. (00:09:00)
Visible crew/equipment: When the horse carriage is ambushed, just as Princess Abigail can be heard screaming "Please, help me", the camera pans downward and a horse wrangler wearing a blue baseball cap can be seen in the lower left hand corner, hiding behind one of the horses. (00:03:20)
Revealing mistake: When all the vampires are saying "for the dark", and one gets staked, there's a mark on his shirt where the stake's about to come through before it actually happens. Plus Buffy's hands are in the wrong place for her to have pushed that stake through, as well as there being no stake in her hand when the vampire gets dusted. Not only that, but the mark isn't even close to the vampire's heart to begin with. (00:34:50)
Visible crew/equipment: In the opening scene where General Clayton is explaining the 4077 to the psychiatrist, the scene changes to the outdoor set and the camera pans to the right. As the camera pans past the hospital, a white 1970s era shuttle van can be seen driving into the set in the upper right corner of the screen. (00:01:35)
Continuity mistake: When the foreman first slaps Simon on the back, the muddy handprint has quite identifiable finger marks, but in the next shot, when Simon is walking away, the muddy shape has changed. In a subsequent shot, the mudprint has disappeared entirely. (00:04:25 - 00:06:00)
Other mistake: After the Doctor tells Bill that Heather's face isn't symmetrical, when he and Bill look into the "puddle" together the Doctor explains that instead of seeing her normal backwards reflection, she's seeing her face "the right way round." The problem occurs in the next shot of the Doctor and Bill seen in the puddle, because the "WOW!" patch on Bill's jacket is properly where it should be, but note everything else is actually backwards. Things such as Bill's color-block top and her denim jacket buttons are on the opposite way. Also note the Doctor's ring has switched hands. Presumably this shot was edited, and the "WOW!" patch was blurred on the left of Bill's jacket then digitally added to the right side, to give the appearance that it's "the right way round" as the Doctor said. (00:20:15)
Visible crew/equipment: When the son of the accident victims is being led through the trauma rooms to see his parents' bodies, you can see Laura Innes crouching under a table in the background directing the scene. Innes was the director of this episode and it was established that this episode took place on her character's day off. Therefore, she should not have appeared in front of the camera at all. (00:32:30)