There's Marty vs. Biff. The Cubs prediction. Lea Thompson's "addition." Tons to explore. Elizabeth Shue JOINS the cast. Crispin "George McFly" Glover LEAVES the cast (the backstory there). PLUS: The Chumps rip on the director's vision of the future, while hailing his ability to string together a complicated narrative. Also: Corrye goes ballistic about the "what are you, chicken" taunt in this trilogy.