Sliding Scale of Adaptation Modification

When creating a movie from a story already well-known in another medium, those making it are often faced with a crippling dilemma. How true can we stay to the source material without risking a failure at the box office? It can be a very hard call for a director. On the one hand, Fan Dumb will cry "Ruined FOREVER" should he change one iota of the source material, and he may find himself a victim of the fandom's ire from then on. On the other hand, not changing a thing can result in either a very poorly-made movie or one that relies so heavily on the source material that people unfamiliar with the work will be completely lost.

The scale runs something like this:
 * 5. Identical Adaptation: A movie in which next to nothing is changed. These rarely fare well outside the established Fandom.
 * 4. Near-Identical Adaptation: A movie that changes the material just enough to gain a PG rating or be of reasonable length. Usually rereleased with a Directors Cut.
 * 3. Pragmatic Adaptation: Probably the ideal rating. A movie that manages to capture the spirit of the original work, while at the same time, embracing the new medium. These are generally big hits.
 * 2. Recognizable Adaptation: Still bears enough resemblance to its source material that it can be realized as an adaptation.
 * 1. In Name Only: Shares only the name and possibly the main characters.

The scale, however, is not set in stone, and often times, there is overlap. Also, Tropes Are Not Bad as any movie in any of these categories can become a great success. However, the further a movie falls from the center, the less likely that is.

This trope is usually applied to movie adaptations -- The Film of the Book especially—although it can be applied to adaptations from movies as well, since other formats (books, comics, television series) have room for more material. See also The Problem with Licensed Games for the video game equivalent.

Anime and Manga

 * Black Lagoon anime
 * Mahou Sensei Negima OAV

Film

 * Doctor Who, when it's considered an adaptation
 * Many film adaptations of stage musicals; excellent examples include:
 * My Fair Lady
 * Fiddler on the Roof
 * The Phantom of the Opera
 * The 2005 version of The Producers
 * Sin City
 * Rosemary's Baby

Western Animation

 * The Maxx animated series

Anime and Manga

 * Fullmetal Alchemist: Brotherhood

Film

 * Holes
 * The Princess Bride
 * The Lord of the Rings (Ralph Bakshi's adaptation)
 * Some of the Harry Potter films
 * Watchmen
 * Brokeback Mountain
 * Kick-Ass 
 * Fight Club
 * The Godfather
 * The animated version of The Hobbit
 * Scott Pilgrim
 * The Little Prince (1974 film musical)
 * The Blue Bird (1976 film)

Anime and Manga

 * The World God Only Knows
 * Super Dimension Fortress Macross: Do You Remember Love?
 * Sonic X (Though the Sonic Adventure Series based arcs could go up to a 4)
 * The Borrower Arrietty

Film

 * Batman
 * Some of the Harry Potter films
 * The Lord of the Rings (Peter Jackson's adaptations)
 * 2001
 * The Last Unicorn
 * Batman Begins and The Dark Knight
 * Marvel's many movie franchises
 * The first Jurassic Park
 * The first Neverending Story film
 * Sweeney Todd: The Demon Barber of Fleet Street
 * Being There
 * Willy Wonka and the Chocolate Factory and Charlie and the Chocolate Factory
 * Annie (Both the 1982 and 1999 versions)
 * 30 Days of Night

Literature

 * The Novelization of Revenge of the Sith

Live-Action TV

 * The Walking Dead

Western Animation

 * The Adventures of Sonic the Hedgehog

Anime and Manga

 * Howl's Moving Castle
 * Fullmetal Alchemist, the 2003 anime adaptation of the manga by the same name.
 * Trigun (anime), though it occasionally goes up to three.
 * Kiki's Delivery Service
 * Tenchi Universe, as an adaptation of the first OVA arc, although it still has the spirit of the show. Tenchi in Tokyo isn't an adaptation, but if it was, it would be somewhere between Type 1 and Type 2.

Film

 * How to Train Your Dragon
 * Much of the Disney Animated Canon (The Hunchback of Notre Dame and The Jungle Book especially)
 * Dragonball Evolution
 * The Last Airbender
 * Eragon
 * The animated version of Return of the King
 * The Secret of NIMH
 * The King and I (1999 animated adaptation -- Disneyfication completely warps the storyline, but the familiar songs are still there)
 * Cirque Du Freak based on the Saga of Darren Shan books
 * The Shining, as directed by Stanley Kubrick
 * Batman Returns
 * Legend of the Guardians: The Owls of Ga'Hoole directed by Zack Snyder
 * The Neverending Story 2: The Next Chapter
 * Thunderbirds (2004 movie directed by Johnathan Frakes. It visually looks like a live-action adaption of the television series, shares the same character names and usually their personalities. The movie however, changes the main disaster/rescue premise of the show to a Lighter and Fluffier, Spy Kids-esque romp. In order to support this genre change, a number of main characters from the series are also given significantly less screentime.)
 * The Power of One movie
 * Sonic the Hedgehog The Movie (Although it is usually considered to be a fairly good adaptation of the spirit of the games)
 * The Wizard of Oz (1939)

Live-Action TV

 * Dresden Files TV Series
 * Battlestar Galactica remake
 * Legend of the Seeker, based of the Sword of Truth series.
 * The 2011 Live Action Adaptation of Ranma ½ was this level at best, depending on the viewer.
 * The Man Who Fell to Earth

Web Original

 * Abridged version of Pinocchio by Phoenix Games

Video Games

 * Bionicle the game and Bionicle Heroes.

Anime and Manga

 * Studio Ghibli's Tales From Earthsea
 * Bubblegum Crisis: Tokyo 2040

Film

 * Shrek
 * Catwoman
 * The Neverending Story 3: Escape From Fantasia
 * The League of Extraordinary Gentlemen
 * The Running Man
 * The Lost World Jurassic Park (Ironically the third movie uses more scenes from the books, despite not being based on one)
 * The Super Mario Bros movie and The Super Mario Bros Super Show
 * Ella Enchanted
 * Cheaper By the Dozen
 * Jumper
 * The Nutcracker in 3D (To both the book and ballet)
 * Stuart Little

Live-Action TV

 * Peter Benchley's Creature

Western Animation

 * Sonic Sat AM, and Sonic Underground

Anime and Manga

 * The earliest concepts of Princess Mononoke, as visible in Princess Mononoke: The First Story. shows that it's meant to be an adaptation of Beauty and The Beast. However, anyone who has existed for more than twelve seconds can tell you that these two pieces of media are nothing alike, and that they don't even share their names, main characters, or broad concepts. One's an epic tale about anger and conflict, the other a fairy tale about a princess and a beast falling in love. It doesn't share its name, it doesn't share its characters, it shares nothing. Thus, it falls under type 0, if type 0 even existed. Most people aren't aware it started out as an adaptation of the fairy tale.
 * Laputa: Castle in the Sky would be a type 1 (In Name Only) adaptation of a chapter in Gulliver's Travels, except Laputa: Castle in the Sky and Gulliver's Travels don't even share a word in common. It does have the spirit of an In Name Only adaptation, capturing the very broad premise of the original work and building almost everything on top. The only concept it takes from the original is a technologically advanced Castle in the Sky called Laputa, and that's it. Almost everything in the film is new.

Film

 * Simon Birch, the film adaptation of A Prayer for Owen Meany, goes from Type 1 to Type 5  as the story progresses, passing through almost every type along the way.