In the previous film, Queen Ravenna had a very close, somewhat mystical bond with her brother Finn, who was her head enforcer. He is also seen during a flashback to when Ravenna received her magic powers. This film, however, makes absolutely no mention of him in either the scenes set prior to the first film or the ones set afterward. In addition, there is no indication in the first film of Ravenna having any other siblings besides her brother.
When Sara and Eric are in the woods after recovering the mirror and he is convincing her that they belong together, she is tending to and has visible wounds on her shoulder and arm. When they begin to make love, the wounds disappear. In the morning, they are back again.
At the Winter Palace, just before he tries to jump, Eric pulls out an axe. Later after having failed the jump and crashed on the roofs, he safes himself with a axe that has a very different blade. The axe shown in the beginning would not have been able to grab the edge of the roof.
In the beginning of the film, when they are playing chess, Ravenna says, "queen takes king." But in chess, the king is never taken (removed from the board). The game ends when the king is threatened (checked) by a capture from which there is no escape (checkmate), not by the capture itself.
In the beginning of the film, when Freya and Ravenna are playing chess, Revenna gives her move as "queen to rook five." This is one form of chess notation. The story of Snow White was published in 1812 by the Brothers Grimm and is generally considered by scholars to take place some time in the 1500's. Standardized chess notation, however, was not invented prior to 1737, when Philip Stamma, who would become one of England's strongest masters, was the first to introduce algebraic notation to Western chess. Of course, since this a reinvention of the story altogether, which is originally fictional anyway, it need not rely on a time line based in fact.
Young Sara has a face full of freckles. Older Sara does not (as Jessica Chastain has a clean face). Freckles can fade with time, especially in a land with little sun.