When Jonathan and Maddy are walking through the snowy wood, they stop just short of the footprints that lead to the den. The footprints that we then see are left by the limping man, who by all accounts drags one foot. Yet the prints leading to the den are almost identical – left and right – whereas one set should obviously look like a continuous print, if a leg had been dragged through the snow. Similarly, when the two of them arrive back at Maddy's car to discover the broken window, there is no evidence of prints leading to the car itself.
During the flashback reveal, where 'Marella' admits to Hannah that she is really Beryl and therefore Hanna's mother, Susannah Hamilton's (Hannah) hairstyle changes several times during what is supposedly the same conversation.
Marella is supposed to have killed herself by putting a rifle in her mouth and pulling the trigger. There were several odd things about the situation, such as the disappearing footprints, but a suicide of that kind would certainly have produced a lot of blood. As she was discovered in the snow, someone would surely have wondered why there was no red anywhere of any kind – even if it wasn't obvious to the husband, the police or paramedics should have noted it.
Towards the beginning of the episode, Carla is annoyed by a man for whom she holds the door, whilst exiting a store. She has several bags in her hands. She chases after him and transfers some bags to her left hand. When she catches him up, she grabs him, with an empty left hand.
During the 'Psycho' illusion, as Adam Klaus is stabbing the woman in the shower, the shadow of his victim can be clearly seen stepping down into what is presumably a trick space under the apparatus, which sort of ruins the routine.
Jonathan & Madeline are in a restaurant for lunch;
Jonathan says he can't watch people eating raw onions - then the long shot shows raw onion rings on his plate.
When Rokesmith's sister arrives at his cottage, we see her through the cottage window carrying her handbag and a large blue and gold coloured bag. Yet when she arrives in the cottage itself, she has only her handbag slung over her shoulder.
There are several things that don't make sense with the nuclear shelter: the toilet's plumbing hasn't been fixed yet, but there is a drain hole in the floor. The bunker is hermetically sealed in the middle of a cliff and lined all round with 50cm of concrete – where is the waste from an ordinary toilet supposed to go? And since when was building something that is supposed to withstand a nuclear blast inside a cliff face a good idea, since cliffs themselves are constantly eroding and wouldn't stand much chance faced with a few megatons? Then there's the door: armour-plated apparently and meant to cope with anything – yet police are able to get through it with a blowtorch.
On discovery of the video camera in the garden, Maddy warns Zola to be careful because "there might be fingerprints." Yet in the next scene we see Maddy having hooked the camera up to the television, manhandling it and pressing the buttons without the use of gloves of any kind.
When Jonathan spots Maddy and Shelford across the bar on their blind date, Shelford's glass of beer is over half empty. When he approaches them, the glass is suddenly almost full.
After the police have taken away Roy Pilgrim, and Jonathan, Maddy and the Flowers wonder what to do next, Jonathan suggests going in by the back gate. As the only person in the house at that time was Francine, who is taken by surprise by their presence, how did they get through the iron gate? We see several times that it is protected by a key code and voice entry system.
The character of Roy Pilgrim must have been a Dickens fan. His rock band was called Edwin Drood, after the last, unfinished Dickens novel The Mystery of Edwin Drood and Pilgrim's home was called Bleak House, just like Dickens' ninth novel.
At the end of the episode when we see Emma Lazarus's stalker with a box, which we know contains her head, he's sitting on a plane back to America and is told to put the box in the overhead compartment. Even given this was before the major security enhancements, all hand luggage was still x-rayed. It would take a particularly terrible security officer not to spot a severed head in a box!
When Maddy says she's going to have a 'shufty' round Norman's room, she hands Antonia an uncooked chicken to "get the lunch on." She goes upstairs, looks in his wardrobe, then in his laundry basket, finding him in the bath, and gives up, going back downstairs, by which time not only is the chicken cooked and ready to carve, but all the vegetables are cooked too. It's feasible that Maddy might have spent a few more minutes looking round upstairs, but a raw chicken and roast potatoes would take a lot longer to cook!
As his wife is making him a nettle sandwich, Sylvester LeFley is on a sunlounger, on his front, having his legs massaged. His wife is watching him. She turns to walk the few paces to him, proffers the plate and he is suddenly miraculously on his back now, looking up at her.
There is a major mistake in plotting in this storyline. As we discover, the suicide of Duncan Proctor was nothing of the sort. They explain away the ambulance coming as some friends doing a prank. But a whole house full of guests has just seen or known about a guy jumping to his death from a high balcony. Why was there no police report? The police would have had to be involved at some point in a suspicious death. It's even down to Maddy to discover that there was no hospital admission or anything of the sort, when the police are now involved in the murder of Felicity, and would presumably have access to that kind of information.
At the beginning of the episode, the Inspector is describing possible suspects and their special skills - one of whom is a seasoned hitman, one of whom is martial arts expert. The third, he warns, is a suicide bomber. How could he possibly know this? Suicide bombers don't exactly make a career of it - it's a strictly one-time event!
The murder itself, when the coroner is examining the body is still believed to be a stabbing. She mentions that the weapon went through the heart and is 'barely a millimetre' in width. This is patently not true, as we see once the weapon is revealed as a spike. Presumably, the writer meant barely a centimetre, since a millimetre would almost make even a needle out of the question as a weapon.
*** Spoilers ahead ***
The setup for the murder is not very smart, and it is actually very unlikely to kill someone like this. In order to kill, the victim should make contact not only with an electrode - the clock, or the pins in case of the Redcap - but also make another contact with either another electrode or ground. In the Redcap, that may have been some metal radiator. But in the case of the judge there is no electrode or ground: his bed is made of wood which is non-conductive. His mattress might have been conductive if it was a very poor quality box-spring - unlikely for a man of his standing - but even so, it is placed in a wooden bed. At most he might have felt a little tingle or a prick when his arm had brushed the bed table, thus making a circuit. But this would certainly not have killed him, nor even stunned him enough to be stabbed without resisting.
When Lenny Spearfish signs the deal with the devil, the signature on the document is signed with a very fine quill pen. When we see it again in the packing crate, having been discarded, the outline of the signature is much thicker.