Character mistake: Ray and Egon are giving Oscar the check-up; Ray suggests to run a "Gammill and Pross Infant Acuity Test", which does not exist and is an inside-joke in the screenplay, since Tom Gammill and Max Pross are a duo of comedy writers. Egon agrees and says that they'll finish with an Apgar score, which is a real pediatric term - but it's a test for literal newborns, not an eight months old one like Oscar. (00:16:05)
Character mistake: At the psychiatric ward, Ray says that Vigo is a XVII century tyrant; it's not a very fitting way to describe him, since he saw the XVII century for just a decade; as the book mentioned, he lived from 1505 to 1610 and was the scourge of Carpathia for the XVI century. (01:16:15)
Suggested correction: Not a mistake, Vigo was a tyrant in the 16th and 17th centuries, Ray chose to label him a 17th century tyrant because that's the century he died in. It would be like calling Osama bin Laden a 21st century terrorist, which is correct, even though he also committed terrorist acts in the 20th century.
