Continuity mistake: In one scene after Hutch is beaten up on the bus, he has no facial injuries. Then in the next scene, they are back.
Continuity mistake: When Patrizia paints her phone number on the scooter's windshield the numbers change between shots, check the 5 for example.
Factual error: It is not possible to have a conjoined twin of the opposite sex. They are similar to identical twins, which are always of the same sex, in that they are formed from a single zygote. In the case of conjoined twins, the zygote fails to divide normally.
Suggested correction: There are always exceptions to the rules and, although VERY rare, it IS possible for conjoined twins to be - rather, end up being - different sexes. There are about 10 documented cases. In one case, is my understanding the conjoined twins started out as males but a genetic mutation (or something) occurred and one male lost his Y chromosome, thereby developing into a female with no ovaries. (The now-female twin would have so-called Turner Syndrome.) I don't have any sources to quote off-hand.
The male would have lost his Y chromosome after the zygote "split", but he was a monozygotic male.
Factual error: When Cruella first drives her iconic car, being in Britain the driver's seat should be on the right side, not the left.
Suggested correction: Cars can be imported from overseas. It's very possible the car was imported from America.
Factual error: In the beginning, it's 1989. The crew chief, Michael Rooker, is wearing Mechanix gloves... which didn't come out until the 1991 Daytona 500.
Continuity mistake: When Tony lies dead, his head is facing right or left between shots, no continuity whatsoever despite Maria not touching him.
Continuity mistake: In the desert digging, the Nova's trunk is open, then shut. (01:42:00 - 01:45:00)
Continuity mistake: An exterior view of the window in the building across the street that the Virtuoso plans on shooting from shows it is comprised of three square panes stacked vertically. When the Virtuoso is inside behind the window, it is one large vertical pane. (00:10:27)
Continuity mistake: When Booth is caught with the egg at his house, Hartley gives a "I know who you really are" speech to him and during this time, he's drinking from a clear glass. He hands Booth the glass as he is walking around. Immediately after handing Booth the glass, you can see Hartley has another glass. Then takes the glass from booth shortly after. (00:17:03)
Continuity mistake: At the prison visiting "Uncle Sally", Dickie sets a box of matches on top of his cigarettes. A little later, the matchbox is behind the cigarettes and the cigarettes are angled about 45° more away from the ashtray. (00:48:12)
Plot hole: Diabolik blinks in Morse code to his accomplice the location of one of his hidden stashes. He says it's in 'the third brick to the left' and the street name, but no address or other reference. She (who previously knew nothing about the location) finds it immediately. It's worth noting that the movie is a faithful adaptation of a couple issues of the comic, but this bit of subplot is a fresh addition and the original hiding spot in the 1963 issue was a plausible one (cave behind a specific waterfall).
Other mistake: William Tillich (AKA Bill Tell) had one suitcase which could not possibly hold enough sheets (or thin blankets) to cover/wrap all the furniture in his motel room like he did. (His suitcase was not very large and also contained his clothes.) He covered an even larger area of furniture in Gordo's house. It isn't clear if he used his own sheets or just happened to find the same kind in Gordo's house.
Continuity mistake: Helen's slipper is at about a 45° angle toward the right of the screen when Miss Willoughby finds it. When Detective Jimmy shines his flashlight on the slipper, it is facing the opposite direction. The second time Jimmy shines the flashlight, the slipper is at a steeper angle. (01:00:33)
Continuity mistake: The height of the stack of magazines on the coffee table in front of John changes with the camera's view. Front views of John show a high stack of maybe 15 magazines. Side views of John show a much shorter stack of several magazines. (00:25:03 - 00:26:07)
Factual error: When pit bull Shadow was chasing Phoenix, the distances between them varied - even appearing to increase - but the pit bull should have been able to quickly close the gap and catch Phoenix. In general, an adult person (about 7 mph) cannot outrun a pit bull (25-30 mph). Also, unless Shadow was trained to stop pursuing Phoenix if she got over the fence, pit bulls are actually quite good at climbing fences. (00:02:38)
Other mistake: The chances that no-one in the approaching truck - three men, including a man standing in the bed facing oncoming traffic - would notice that Danny had a front seat passenger are very low, if not zero. Even after Motley got into the second row seat of the truck, but did not get down right away, the men in the truck had turned around and were following Danny but still did not notice Motley. (00:10:00 - 00:10:27)
Continuity mistake: The door had multiple small rectangular glass panes enclosed in wood frames, but the glass pane that Alan Schaefer's head/body went through was larger and no wood frames were visible. (00:40:28)
Deliberate mistake: The view looking out the windshield showed the man on the bicycle had stopped when he was in front of the car's passenger side, but the outside view showed the man still coming to a stop and then tilting his bicycle. (00:07:12)
Other mistake: Blood gushed out of the bound man's lower inner arms that were slit with a knife from below the elbow to the wrist (then turned toward the ground). A switch to an aerial view showed no additional blood dripping (while he was still alive). Also, blood would not pour out of his arms to the ground in a horizontal stream like it did. (00:02:04 - 00:02:27)
Revealing mistake: The blemish/mole that was on the right side of Ghost's nose showed up on her left side (and she was not looking into a mirror). (00:57:40)