Continuity mistake: The green Alfa in the opening minutes has its side, and mirror, wiped out by a lorry. For the next 5 minutes it then drives around in perfect condition. (00:05:43)
Factual error: The movie starts in 1985, jumps '5 years later' and then back to Sasha Luss, then '3 years earlier'. So, in her crusty apartment in an impoverished neighbourhood of 1987 Soviet Russia, Anna is filling a form on her notebook-style laptop, too modern for the era. It looks like a NEC UltraLite (considered the first notebook style laptop) which didn't even come out until 1989, let alone the likelihood of someone in the USSR having one.
Visible crew/equipment: When Lionel returns to the jazz bar and discovers Billy Rose has been killed (framed as a suicide), you can see two people standing in the shadows to the left of Lionel as he enters the main room where the stage is located. A man is hunched over, whilst a woman is standing still wearing what looks like a dust mask. (01:32:27)
Continuity mistake: During his conversation with the director, while discussing his costuming, Dalton's hair changes from messy and curled to gelled up and straight.
Factual error: While handling the ignition coil cable to the distributor cap, Joe Pesci tells De Niro that the timing chain needs adjustment in his truck. A truck of that year with an inline Chevy motor would not have a timing chain at all, instead this truck would be equipped with a direct drive timing gear. Even if it had a timing chain, it would be behind the water pump and a cover. It would have been a several hour job to replace, not possible to adjust it.
Continuity mistake: When they finally arrive at the bottom of the sewer, Eddie's bandage is on a different cheek. (01:59:00)
Continuity mistake: In the final battle, Wasp and Ant-Man are in the van trying to get the quantum tunnel operational. We cut back to the fight and we can see Ant-Man there too, fighting in his giant form. (02:22:20 - 02:23:00)
Factual error: The strong current of the river the main character falls into carries him to a considerable waterfall. There is not, nor has there ever been, a river of that kind in Flanders' Fields, let alone a waterfall. Anyone who has any insight into the geography of the region will tell you it is flat as can be. The largest body of water, the Yzer, gently meanders and flows into the Channel, even during really rainy times.
Continuity mistake: During the interview, while sitting, his striped pants are unzipped for a few cuts, then they are zipped in later shots.
Character mistake: Selena Gomez drives into town in a fully restored 1967 Pontiac Le Mans, which is a long box shaped car. However, when confronted with Bill Murray and Adam Driver, Adam Driver complements her on her 1968 Pontiac Le Mans, which is a completely redesigned shorter curved body style. The two look nothing alike.
Factual error: It is not possible that Pitt could have gone up to the ship when it was already blasting off. There was literally fire in the tunnel.
Factual error: Throughout the movie, scenes of the chess tournament room show the American flag incorrectly vertically hung (stars on blue upper left is proper), while the Soviet flag is correctly vertically hung. No real American vs. Soviet tournament would make that mistake.