But rather than simply inserting deleted scenes, Jackson approached this Extended Edition as if he were creating a whole new version of the film. He and editor John Gilbert carefully evaluated material to be integrated into the film, and then worked to bring each scene up to the same polish as the rest of the feature – visual effects were completed, dialogue was recorded and sound effects created.Based on what I’ve seen of the discs so far, these are no idle claims. Each of the three films in the trilogy – The Fellowship of the Ring, The Two Towers and The Return of the King – has its own box with four discs. Two of the discs in each box are labeled Appendices and Jackson himself introduces these, explaining the bonus features and how the menus should be navigated. The features include dozens of good-sized documentaries about various aspects of the filming; galleries with thousands of categorised images (storyboards, artwork created for the production, behind-the-scenes photos); four separate feature-length commentary options (by the director and the writers, the cast, the production and design teams, each group providing a specialised perspective on participating in one of the grandest movie epics ever); and detailed interactive maps, based on the ones that Tolkien created for his books, which allow the viewer to trace the routes taken by various sets of characters (a mini-screen simultaneously plays part of the relevant scene from the film, so the various complicated place names can be easily related to the landscapes in the movies). Whoever put this material together must have had a lot of fun doing it.
Of course, to get through all these features you have to be an obsessive fan of the trilogy, or a Tolkien-nerd, and also have an obscene amount of free time on your hands. It’s staggering to think of how much time would be required to navigate everything on this set. The films by themselves add up to around 12 hours and if you were to listen to all four of the commentary tracks (I did say you have to be obsessive), that means a cool 48 hours spent in front of your TV screen. The documentaries run into several hours too, and it’s impossible to estimate the amount of time needed to see all of the images in the galleries or to study all the map routes.
I doubt I’ll be able to do all of this anytime soon, but for now I’ve watched the extended version of The Fellowship of the Ring as well as bits of The Return of the King, and the extra material has been quite good, especially the quieter scenes that punctuate the grand moments (this is something I occasionally thought was missing in the films when I saw them on the big screen): such as the melancholy scene early in the first film where Frodo and Sam watch a group of ghostlike, fading elves marching slowly towards the ships that will take them to Valinor; or the confrontation between the heroes and Sauron's sarcastic messenger (known as the “Mouth of Sauron”) outside the Black Gates of Mordor just before the final battle begins.
More info here, here and here.