There's a certain level of Unintentionally Unsympathetic to Robbie as while he is convicted of a horrific crime he didn't commit, the movie points out he missed the fact none of the family except Cecilia was willing to think him innocent on the flimsiest of pretenses. His attempt to better his station put him among a bunch of Upper-Class TwitJerkass types who quickly turned on him.
Briony's actions regarding the happy ending she gives to Robbie and Cecilia in her novel: is she genuinely making amends to people she wronged the only way she can and knows how, or is she selfishly, cravenly and dishonestly attempting to rewrite history and cover up her own actions to make herself feel better, and hiding behind atonement as a justification? What's more is that in the Distant Finale Briony claims she will be suffering from dementia. So if she writes a happy ending for Robbie and Cecilia, the dementia may make her think it's true...
In the book, the reader is treated to a very harsh portrait of the young Briony in the lead-up to Lola's rape. Considering this is meant to have been written by her older self, is it a reliable interpretation of events or is Briony's self-loathing and regret making her an Unreliable Narrator? To go even further, writer!Briony doesn't actually know that Marshall was Lola's rapist or even that Robbie was innocent, only that his and Cecilia's relationship was consensual. Rereading the book is a bit of a Mind Screw.
The book's vagueness of the offpage actions of Marshall and Lola also include some of this. The general picture one could get is the young Lola got in over her head and Marshall couldn't understand the word "no". But even if this is so, how exactly they got married is another major question. It is possible he purposely seduced his victim to marriage so she could not testify against her. It's also possible if with the understanding of the comparisons between Lola and her mother she may have blackmailed him after he made his fortune to expose him for the rape unless she got her way. Or it was a little bit of both making them both a Karma Houdini to Robbie and Cecilia's plights.
Unintentionally Unsympathetic: Briony's elder self, whom the audience is clearly supposed to feel sorry for due to her guilt and oncoming dementia. However, the whole mess she describes was almost entirely her fault, brought about by her envy, cruelty and sheer stupidity. Her attempt at giving Robbie and Cecelia a happy ending in her book comes off as a truly pathetic attempt to hide from her guilt, although even in fiction they don't forgive her.
Cecilia knows Briony has an overactive imagination. She's clearly afraid of Briony showing the letter to her mother. You'd think as soon as everyone was looking for the twins, she'd at least take Briony aside and explain the situation. Granted, it's awkward for your little sister to walk in on you having sex, but she also could have at least said something to her after Briony catches her and Robbie in the library instead of silently leaving, thus making Briony confused and ignorant to Cecilia's consent to the encounter.
Cecilia and Robbie never consider Marshall as a possibility for the real rapist until Briony tells them, even though he was the stranger in the house that night and had showed up at dinner with a scratch to match Lola's bruises. (In an interesting example of Not So Different, they seem to have settled on Danny Hardman as certainly as Briony settled on Robbie, and based on as little evidence, prompting Robbie to remark that they "owe Able Seaman Hardman an apology.") Though this is Briony's fictional version of Robbie and Cecilia, it may be true or it may be Briony's imagination.
Despite garnering nominations in other parts of the awards circuit, including the BAFTAs and the Golden Globes, Keira Knightley and James McAvoy ultimately failed to earn Oscar nominations. Though both categories were especially crowded with talent during the 80th Academy Awards, it doesn't stop fans from complaining that they could have replaced Ellen Page or Johnny Depp.
Genius Bonus: After Briony has accused Robbie of raping Lola, she is shown standing in front of a stained-glass window of St. Matilda, the patroness of the falsely accused, and also the subject of a nursery rhyme that begins "Matilda told such awful lies/ She made one gasp and stretch their eyes..."
One of Benedict Cumberbatch's earlier film roles. He uses a high-pitched voice to add to the Upper-Class Twit feel, making him harder to recognize now.
Alfie Allen, here having just a couple of scenes as Danny Hardman, would gain greater exposure as Theon in Game of Thrones.
Signature Scene: The Dunkirk oner. While people had questioned the shooting of the scene as a oner since the single shot adds little to the story (it wasn't supposed to be one, but became one due to time constraints), the result was found to be quite memorable when taken on its own as a cinematic painting of the chaos at Dunkirk. The scene itself ended up being somewhat more famous than the movie itself.