Until the filming was complete, Mirror Mirror was known as The Untitled Snow White Project. Though director Tarsem Singh's intention was to make a family-friendly action comedy, he admitted to the press that he was disappointed with the title Mirror, Mirror. He said in an interview that we would have preferred the simple title of "Snow."
This is the first adaptation of The Brothers Grimm: Snow White where both the characters - Snow White (Lily Collins) and the Evil Queen (Julia Roberts) - have a romantic relationship with the Prince (Armie Hammer).
When Snow White is about to go outside the castle for the first time, you hear the clanking of the knights axes but you can see clearly that they don't touch each other.
Around 18 minutes of this film, in the forest, as the Prince is bidding adieu to Snow White, He was first standing on the left side of his companion, Charles. One second later, he was standing on the right side of Charles.
After the Queen finds out Snow White is alive she storms to her room wearing the Elizabethan stiff collar. She enters the closet with the collar on but in the next shot of her approaching the mirror from inside the closet it disappears.