Award Category Fraud: An uncommon variant. Keira Knightley campaigned as lead but ultimately failed to place at the Oscars. While it can be argued that she was a co-lead (and marketing materials made sure to sell her as one-half the face of the movie), Saoirse Ronan was submitted (and snagged a nomination) as Best Supporting Actress. Briony is in no way a supporting character, especially to Cecilia, but Ronan was relegated to the supporting categories largely because she was usurped by more famous actors, her young age, and the fact that, much like Lion, she plays only one part of Briony's life, while Keira Knightley is always Cecilia.
Billing Displacement: Saoirse Ronan (and all other iterations of Briony) is usurped by Keira Knightley and James McAvoy so often that she tends to warrant only a tiny fraction of film posters and promotional material, which milk the more famous stars' faces for all their worth (as Ronan wasn't famous yet). Though the plot centers on Cecilia and Robbie and their doomed romance, Briony is still unquestionably the main character who the narrative follows the closest. See Award Category Fraud above.
California Doubling: The British seaside town of Redcar doubled as Dunkirk beach, and its old cinema even appeared in it. Lincolnshire also doubled for scenes in the French countryside.
Cast the Runner-Up: Joe Wright had wanted Keira Knightley to play the role of Briony in her late teens, but she immediately liked the character of Cecilia, and also wanted to get away from playing girls on the brink of womanhood and play a more mature character for once.
James McAvoy was always Joe Wright's only choice for Robbie. Although he did meet with others in case he turned it down, he was offered the part without an audition.
Vanessa Redgrave was likewise the only choice for the elderly Briony.
Dawson Casting: 25-year-old Romola Garai was cast as 18-year-old Briony. This has the effect that, when Briony is in scenes with Cecilia as an adult, she's actually three years older than Keira Knightley, since she continues to play Cecilia throughout. Justified since the one scene adult Briony shares with Cecilia is actually fictional, so Briony would only imagine Cecilia as she was.
Fake Brit: Irish Saoirse Ronan as English Briony Tallis. Averted with Romola Garai and Vanessa Redgrave, who play Briony's older selves - as they are both English. James McAvoy is a borderline case. He's Scottish, doing an English accent.
Playing with Character Type: Invoked by Keira Knightley. She was approached to play the adult Briony but asked to play Cecilia instead - saying she'd had enough of "coming of age ladies".
Posthumous Credit: John Normington, a veteran of stage and screen, has a minor role as a vicar, but sadly died before the U.K. release.
The Red Stapler: The gorgeous green dress worn by Keira Knightley is practically iconic. Replicas of varying quality can still be bought in several online stores.
Referenced by...: The Italian ice dance team Charlène Guignard & Marco Fabbri performed to the Atonement soundtrack for their free dance during the 2020-2021 and 2021-2022 competitive seasons.
Serendipity Writes the Plot: The Dunkirk scene wasn't supposed to be a Oner. It had to be one because all the extras can't stay for very long and the environment conditions gave a very short window for filming, so Director Joe Wright came up with the oner idea so everything can be done in one go.
Throw It In!: In the DVD Commentary, Joe Wright reveals a lucky fluke that got caught on camera during the scene just before Robbie discovers the school girls massacre. At the point where he removes his helmet, the weather was cloudy. As he looks up the sky, the sun started shining and then got cloudy again the moment he put his head down.
during the 2020-2021 and 2021-2022 competitive seasons.