Continuity mistake: When the guards come to take Elizabeth away in the beginning, before she is queen, Lord Dudley has his back to the camera and is saying goodbye to her. You can distinctly see the clasp of a necklace on the back of his neck, but in the next few shots, there's nothing there.
Continuity mistake: In the director's narration on the DVD he points out a great mistake they made while editing the film. There is a scene where Elizabeth is dressing. In one place where they spliced two shots together, she starts out sitting down only partially dressed. In the very next frame she has stood up and is quite a bit more dressed. After watching the commentary, the mistake is completely obvious.