- In 'Sardines', when Rebecca and Ian are waiting to be found by the other guests, Ian remarks that it 'could be a long game'. This gains something of a double meaning when it's revealed exactly who 'Ian' really is and what he's up to - he's been playing a long game this whole time.
- In 'La Couchette', Jorg sleeping in Kath's bed comes across him just not bothering about which bed has been assigned to which passenger. The ending reveals that the real reason is because Yves (the dead man) was already sleeping in his bed when he arrived (which is why Maxwell killed him), so he just took another vacant one. It also gives some clarity to his annoyance about being made to switch beds. If other people don't follow the rules about assigned beds then why should he?
- From the same episode: Maxwell being the killer makes perfect sense. He's a doctor so if the death is discovered, he can take control of the situation and shift any potential blame away from himself. And also, his field of expertise is pharmaceuticals. He could have easily slipped Yves some form of medication that would have been lethal in a certain dose, or some kind of lethal drug. And who would suspect a doctor with medication in his possession would be up to something sinister?
- All the episodes come with official, movie-style posters featured on the official websites. Most of these contain some kind of clue to the twist or ending of the story - for instance, the poster for "A Quiet Night In" features a bloody bullet hole and "The Twelve Days of Christine's" poster shows half of Christine's face fading into a faint, ghost-like image.
- May's horrified scream at the discovery of Hugo's body in "Once Removed" takes on a new meaning when you learn that she had only meant to divert a hitman meant for her onto one of the people responsible for hiring him. Now she learns that her actions also resulted in him killing some poor guy who just happened to be in the wrong place at the wrong time.
- The titular number 9 in The Referee's A W***er has nothing to do with the episode's changing room setting: it comes from a picture of the home team's captain with a 9 on his shirt. But the captain and the referee are revealed to be lovers. So it turns out that the referee really has been inside no. 9.
- At the beginning of 'La Couchette' we see Maxwell alone in the cabin (apart from Yves who is dead) and he seems generally relaxed, preparing for a good night's sleep. The ending of the episode reveals that Maxwell killed Yves, believing he was Jorg. Maxwell being that calm and at peace soon after murdering someone in cold blood while alone and not having to put on any kind of act shows just how incredibly cold-blooded and methodical he is.
- In 'Sardines', it seems pretty much everyone knows that Andrew was (at the very least) publicly accused of abusing a child - but he remains an important and powerful figure in the local community, and no one seems to have done anything about him until "Ian" came along. Even one of his own daughters doesn't want her children around him.
- It is mentioned that the police were involved, but Andrew paid Pip's family to leave, so supposedly, not much could have been done, but since almost everyone knew and did not act is a bit sad, but again, not much possibly could have been done about it since Pip and his family already left.
- The incident apparently involved Andrew "Teaching the child to wash himself," and 'Stinky' John either witnessed the abuse or was abused in the same manner, as seen by his reaction to the smell of the soap from the bathroom. Suddenly his aversion to basic personal hygiene isn't so funny anymore...
- Another bit of Fridge Horror: if Andrew hadn't made Jeremy, the people under the bed and 'Stinky' John get inside the wardrobe, then someone might have noticed Pip and been able to stop him in time, and/or he wouldn't have been able to get all the people in the house in the same place. By making everyone get inside the wardrobe, Andrew's basically condemned them all to death. And while Andrew had it coming, and some of the others were pretty unpleasant, they didn't deserve to be burned alive.
- "The Devil of Christmas" revealing that the entire set up was a Snuff Film makes you wonder whether or not Brian ("Julian") and Nancy ("Celia") knew this - and in the case of the boy playing "Toby", whether his parents knew (given a casual comment from Dennis early in the episode that casting a child was difficult due to the subject matter of the piece.) If not, did they ever wonder about the movie's release and try to track it down?
- Dennis's casual attitude about accepting the job because he couldn't get Worzel Gummidge is pretty chilling too. It also raises the question of who would hire a professional director, cast and crew and build sets for a movie not intended to be widely circulated.
- In "Diddle Diddle Dumpling", the blood on David's hand is wet - but Ted lives in Norfolk, some distance from David's family, who appear to be in London. If he'd only killed Ted and driven back, the blood would have dried in that time. Now, remember him talking about how the twins should be together ...
- In "The Riddle of the Sphinx", Tyler told Squires about Nina/Charlotte's revenge to make sure he'd do the crossword puzzle. But what explanation could have Tyler given him to convince him to play along with Nina's plan, and why would Squires do it? Fair enough on not reporting Charlotte to the police, but why not just call security when she showed up instead of drugging her, which would've been extremely risky?
- In "Diddle Diddle Dumpling", after the HUGE reveal that David and Louise had a twin who died, it's revealed that the shoe at the center of the episode was half of an old pair of David's shoes. OK. David is a little crazy and needs therapy; he might miss that it's his shoe. But how does Louise not at least speculate that maybe it's David's shoe, with all the fuss David's been making about this shoe over the past year?
- She probably did know it was his shoe. She was obviously concerned about it right from the start, even before David became obsessed. But what good would telling David do? He'd deliberately placed the shoe there for him to find and had apparently forgotten it in the space of a jog around the block. Clearly David's projecting the loss of his son onto his obsession with the shoe ("They're a pair. They belong together") and Louise probably decided that the best way to cure David, both of his obsession with the shoe and his clear depression over the loss of their son, was to give the shoe its pair. Hence the plan for Ted to claim the shoe which had the added benefit of physically removing it from the house. Both of them essentially treated the shoe as their dead son - David obsessed over it and was convinced a pair belonged together, Louise just wanted to forget and move on.
- In "Once Removed", how does Viktor, a hitman, have not even a clue what May looks like? Did May's husband Charles (who ordered the hit on her) not even give him a physical description? Even better, why not a photo he'd printed off?
- Added to which, didn't he find it strange that the house immediately after number five was number nine? And if he was going the other way, wouldn't he have passed the real number nine first?
- In "Tempting Fate", how come nobody finds it odd (until the end) that Frank videotaped himself committing suicide, yet "officially" died cutting his leg and bleeding out when he fell through a glass table? Did they all just assume he failed before they cut off the tape?