Factual error: The Asian girl in the future was wearing her collar with termination charge for a very long time around her neck. When it was removed there was no mark, tan line, or indention or anything left behind, as if it had never been there. Yet all evidence points to years of endless wearing. (01:00:00)
Continuity mistake: When the Fabricant of the future is told this is to remove her collar, at which point she is killed, they lay her back and her arms are at her side. They pull her to burn. Her arms are in a position to not bend properly when reaching the threshold. Shot cuts and suddenly her arms are turned so they easily fold up. (02:19:25)
Continuity mistake: As Luisa Rey is leaving her building a yellow Maverick passes her followed by a yellow Checker cab. 14 seconds later when the camera angle changes, following Luisa up the street, the yellow Maverick can be seen, but the yellow Checker has disappeared. (02:06:20)
Continuity mistake: When the old composer is sitting on the couch and directing the young guy on music, there are pillows on the couch. The positions of the pillows change subtly between shots through the scene.
Factual error: In Luisa's home there is a calendar for September, 1973. The dates are assigned to the wrong days of the week. (01:53:05)
Chosen answer: Jim Broadbent's publisher character Cavendish has one but it is very easy to miss. It can be seen for a split second when he is about to get into bed as a young man with Ursula. The Comet is the subtle link, but each protagonist is more overtly linked by their actions or what they leave to history. Frobisher reading Adam Ewing's Novel. Luisa Rey reading Frobisher's letters and playing his Cloud Atlas Quartet. Cavendish reading a bound copy of Luisa Rey's Novel while on the train. Sonmi's fellow fabricant watching and being inspired by the movie that was made about Cavendish's adventure. All their actions culminate in the redemption of Tom Hanks in the final story.