Passage: The first two films were released on standard two-disc edition DVDs containing previews of the next film. The success of the theatrical cuts brought about four-disc extended editions, with new editing, added special effects and music. The extended cuts of the films and the included special features were spread over two discs, and a limited collector's edition was also released. The Fellowship of the Ring was released on 12 November 2002, containing 30 minutes more footage, an Alan Lee painting of the Fellowship entering Moria, and the Moria Gate on the back of the sleeve; an Argonath-styled bookend was included with the Collector's Edition. The Two Towers, released on 18 November 2003, contained 46 minutes extra footage and a Lee painting of Gandalf the White's entrance; the Collector's Edition contained a Sméagol statue, with a crueller-looking statue of his Gollum persona available by order for a limited time.

Question: What improvement did the first two films produce?
new editing, added special effects and music