Plot hole: There are several parts of the murderer's plan that are based on pure convenience and/or against all odds, moreso than in the novel due to particular choices in the aesthetics or plot. The murderer (who can't exactly sprint around with cat-like motions) gets to the General and kills him in a gruesome manner, reaching a victim entirely in the open, with the island lacking any cover, not even a tree. Vera happens also to scream providing a diversion; unlike the book, the killer does not do anything to induce her hallucination and split the group, nor sabotages the lights creating a dimly lit environment that makes the trick more plausible.
Episode #1.1 - S1-E1
Factual error: Unlike Christie's novels, there is no explicit statement of the date - the original novel started on the August 8th, which is compatible with what is shown here; Vera is interviewed and the letters are all posted on August 2nd 1939, which would fit. However, there's a problem when Vera changes seats en route to Soldier's island. A passenger is reading the Daily Express, and the headline is from August 29th of that year. Too much time elapsed and it's the end of the Summer while the chat between Emily and Vera implies otherwise; it's also Tuesday but the doctor comments "It's been a long week" when he apologizes at dinner - the weekend feels a more appropriate time for a party and gathering as shown. (00:06:15)
Episode #1.1 - S1-E1
Continuity mistake: The unsuspecting group is on their way to the mansion. The ferryman goes back to his boat leaving the luggage he was carrying in the middle of the meadow. Judge Lawrence Wargrave asks "Davis" to take his suitcase. Davis picks up the judge's black suitcase in his right hand, switching his brown one to the left hand. Next shot and it's the other way around; he carries the judge's in his left and his own with his right. (00:12:20)
Episode #1.1 - S1-E1
Continuity mistake: As the guests enter the house for the first time, Doctor Edward Armstrong in his white suit is amongst the first ones to go through the door. Philip Lombard is right behind him, and he walks past the door when the doctor reaches for his hat - but in the next shot, the doctor already has his hat in hand when Lombard hasn't gone past the door yet. (00:12:45)
Episode #1.1 - S1-E1
Continuity mistake: When Sam Neil flinches looking at the rhyme in his room, the shadow he casts on the door is obviously different from shot to shot. (00:16:25)
Episode #1.1 - S1-E1
Continuity mistake: Dinnertime; the door opens, and some guests (the doctor and Davis) have different positions (elbows / hands on/off the table) they switch back and forth on matching under specific camera angles. (00:25:40)
Episode #1.1 - S1-E1
Continuity mistake: At the beginning of the dinner, Dr. Armstrong tells Judge Wargrave "We met before, you know?" Vera Claythorne picks up her glass twice in two separate shots. (00:26:05)
Episode #1.1 - S1-E1
Continuity mistake: General John MacArthur starts commenting, off-camera, that he knows the poem by heart. Notice his hand and how the index is on the rim of the glass. He is not even holding it in the next shot, and Marston's and Brent's hands are lower. The mistake repeats itself seconds later when Emily Brent gets in Vera's face with the comment about the 'poem'; McArthur is drinking from the glass if we believe what we see at the edge of the frame when she speaks, but he's not doing that in the other shots. (00:26:30)
Episode #1.1 - S1-E1
Continuity mistake: While Mrs. Rogers is cutting the roast, Wargrave is entertaining Miss Claythorne with his jokes. She takes a sip, lowers the glass, but in the next shot she's doing it again. (00:27:30)
Episode #1.1 - S1-E1
Continuity mistake: When Marston asks the doctor if the Owens are "the fun-loving type", his hand is off the glass, but he's playing with it in the next shot. The mistake is confirmed by subsequent shots; he always has his glass when the camera is to his left, never when the camera is to his right. (00:30:00)
Episode #1.1 - S1-E1
Continuity mistake: During the seething confrontation between Armstrong and Marston, several small continuity issues happen; Marston is looking or not looking towards Sam Neil, and when he mockingly extends his hand over the table, Toby Stephens' is on or off the table. (00:31:00)
Episode #1.1 - S1-E1
Continuity mistake: Marston asks the General which battles has seen his involvement. Lombard's cigarette loses an inch in the space of a cut. (00:32:15)
Episode #1.1 - S1-E1
Continuity mistake: Vera and Emily are having coffee after dinner. When Miss Blake tells Vera that her school must not be a particularly good one, Vera is picking up or putting down the cup depending on the shot. (00:33:30)
Episode #1.1 - S1-E1
Continuity mistake: The fateful "Swan song" record begins to play, and the doctor is the first to be called out. He is smoking with the cigarette in his left hand, but when he bolts up, the cigarette in foreground is held by a right hand. (00:34:00)
Episode #1.1 - S1-E1
Continuity mistake: The doctor offers a glass containing a mild narcotic to Mrs. Rogers. She looks at her husband, who nods to indicate that she may take it. Without anyone near, the bottle of sleeping powder changed spot on the drawer. (00:37:20)
Episode #1.1 - S1-E1
Continuity mistake: Miss Brent excuses Rogers saying "We'll ring if we require anything further." She says the phrase between two shots, during which the doctor is drinking at first, then he isn't. A similar event happens seconds later when the General speaks; Armstrong brings the arm up to drink, already brings it down at the cut. (00:39:30)
Episode #1.1 - S1-E1
Continuity mistake: Marston vomits blood which goes on Vera's cheek - it appears suddenly from one shot to the next, though. (00:44:20)
Episode #1.1 - S1-E1
Continuity mistake: Inside Marston's room, Lombard opens the cocaine box picking the lid with the right hand, which turns into the left in close-up. (00:45:20)
Episode #1.2 - S1-E2
Continuity mistake: During breakfast, Vera asks Armstrong "Was it you, doctor?" The Judge next to her is buttering the toast, which is an action he stopped doing, putting the knife down, in the previous shot. (00:02:00)
Episode #1.2 - S1-E2
Continuity mistake: When the doctor during breakfast has to defend himself from Vera's inquiries, Charles Dance has both hands on the table when filmed from his left, just the right hand when filmed from his right. (00:04:10)
