During Number Six's exercise routine, he can be seen using a high bar, swing rope and punch bag. However, on the reverse shot of him using the punch bag, the high bar has disappeared.
Number One usually rings on the big red phone, or the regular red phone, but in this episode he calls on the yellow phone.
The computer states that Number Six takes his daily morning stroll at about 6:30 am, yet when the activities supervisor sees Number Two with a activities prognosis report on Number Six, she states the time as being 10:19 and that #6 should be taking his daily stroll.
When Number Six is in bed during the beginning of the episode, his pillow changes position from resting flat on the mattress to laying on the headboard.
Number Two watches Number Six buy a newspaper and sweets for the old lady. Number Six takes his credit card out of his pocket multiple times without putting it back in.
Number 6 takes the watch-maker's daughter to go see her father, but when they enter his watch-maker's shop, the sign hanging on a pole out front says Cafe.
The footage where the retiring Number Two's chair rises is reused from the show's opening credits. When shown in the episode, the footage is zoomed in and blurry.
The front door for Number Six's place automatically opens for him when it senses his approach. However, he has to open it manually at the beginning of this episode.
In the scene in which Number Six visits Number Two to warn him of the assassination plot, Number Two's line "...it's the little watchmaker that concerns you", is dubbed over the original dialogue, and Number 2's lips can be seen moving at one point when there is no audio.
Just before Number Two offers coffee and tea to Number Six, Number Two's lips are moving but nothing is heard.
When Number Six goes to warn Number Two, Number Two brings up jamming. Number Six replies without moving his lips.
Number Six's Kosho opponent jumps up on the ledge and slips. He reverses and runs back along the ledge. When this happens, a crew member can be seen standing in the shadow behind the Kosho set.
During the brief footage of the chess game, a Welsh flag (red dragon on green and white background) can be seen on the Village flagpole.
When Number One Hundred switches Number Six's watch, you can see the hour and minute hands are not in the same position; surely Number Six would notice the time on his watch was now different, even if it had stopped.