Continuity mistake: During the sequence involving Rory and Isaac leaving town with the latter disguised as Kahler-Jex in order to distract the Gunslinger so the Doctor can get back to the TARDIS, parked somewhere outside of Mercy, only to find Jex's ship instead, while Amy and Jex wait back at the sheriff's office, the Sun changes position several times, as do the shadows cast as a result. Most noticeably, when the Doctor finds the cable running from Jex's ship to town, the Sun is quite low, as if close to sunset - while appearing high, as if closer to midday, in the scenes of Rory and Isaac distracting the Gunslinger taking place at the same time. During the scenes of the Doctor finding Jex's ship and Amy and Jex in town, it is also earlier in the day.
Continuity mistake: When the Doctor is at the Tower of London with Amy and Kate, he claims he needs some air. When Amy follows him she follows him twice, in two different shots. The first time on 'ground view' walking and the second time on 'above view' running. (00:21:20)Shadow5
Continuity mistake: When Rory finds his dad on the spaceship, Brian is lying on a gurney next to the two farthest slabs, which are empty. When Amy and the Doctor come through the portal to the spaceship, Brian's gurney is between the two closest slabs, with Rory lying on the closest one, which previously had a completely different person lying on it.
Continuity mistake: When they are back in the cemetery at the end, the Angel shows up right behind Rory. In the first shot facing Rory, as the camera zooms in on a close-up of the Angel, the Angel's right arm/hand is pointing straight out, and its left open hand is up in a grabbing position. After River asks where the hell it came from, in the Angel's next close-up and all subsequent close-ups, its arm/hand positions are reversed - left hand is pointing straight out and its right hand is up. Yet in every shot of the Doctor, River and Amy together, in the foreground we see the Angel's left hand is up in the grabbing position. (00:37:35)Super Grover
Continuity mistake: When Clara asks the "girl" coming down the stairs if she's a friend of Angie's, and the "girl" replies in a monotone, in the shot facing Clara the girl-robot is seen nearly at the bottom of the steps, but in the next shot facing the "girl", she's suddenly higher up the stairs. (00:12:05)skater49th
Continuity mistake: While Clara shouts, "I don't know where I am," over and over, the Doctor sonics his way into the house. When he kneels beside Clara, then notices the 'girl' on the stairs and stands up, in the shots facing him we can see that the young actress stands on the step facing the stairway (note her legs), with her hand at her side, but in the shots facing the girl she stands facing the door with her hand on the banister. (00:14:20)Super Grover
Continuity mistake: When Clara is asleep in bed after the Doctor prevented her from being downloaded by the people in the Shard, he sets up a vase of flowers, a glass of water and a plate of Jammie Dodgers on her bedside table. The positions of the glass, the cookies on the plate, and the torn-open package the cookies came out of is seen when the Doctor leaves a half-eaten cookie on the plate in a close-up. When Clara wakes up, however, the cookies on the plate, the packaging and the glass have all changed positions. (00:18:20)skater49th
Continuity mistake: While the Doctor and Clara are talking and realise that she now possesses extensive computing knowledge, in shots facing the Doctor he has his hands raised in various gestures or by his mouth, but his hands aren't visible in shots facing Clara. (00:22:15)skater49th
Continuity mistake: When Clara and the Doctor watch the lights going out, they first stand in front of the chair, but when the Doctor notes that some planes have WiFi, they stand behind the chair. That chair switches from in front of them to behind them another couple of times. (00:24:00)Super Grover
Continuity mistake: Miss Kizlet wears a large silver brooch on her suit's right lapel in every shot of her, but after Clara notices the lights going out behind her house, when it cuts back to the office Kizlet's brooch switches to her left lapel just before it cuts back to the Doctor and Clara, and since the brooch has a distinctive design we can tell that it's a flipped shot. (00:24:10)Super Grover