Old Guard Versus New Blood

When something goes from one medium to another, it's because of two elements:
 * 1) It's popular!
 * 2) Producers like money!

Moving something to a new medium is a way of breathing new life into an existing product which generates two things. New revenue from the fans, and new revenue from potential fans who for one reason or another never were into it in its original medium, but might get into it here.

This is where the problem arises. Take for instance a comic book being turned into a movie. Most comics have up to 70 years of Backstory, cool sequences, and ranging from a handful to an army of cool heroes and villains. All that has to be crammed into a two-hour presentation or the fans are upset. Meanwhile, it has to be perfectly understandable, and—more importantly—easy to follow, or else the new blood won't like it.

Ultimately this leads to a dangerous balancing act, one that is rarely done right, although producers appear to be getting better at it. You need to throw in enough of the classics and not change things too much or you alienate the fanbase, but at the same time you can't rely on in-jokes or backstory or you'll lose the new blood. While the fanbase may be more loyal, the new blood represents more money for the new genre, so as far as the scale goes it almost always tips to the new blood side.

Before continuing, it's important to understand two things. First of all, any examples here are at best subjective. For this reason, an example could show up in more than one location under different arguments. This is allowed. Everything has an implied "arguably" in front of it.

Secondly, an example being in any of the three categories does not necessarily indicate that it's bad. A movie that has nothing to do with the original premise can still be enjoyable, as can one that is very hard for newcomers to follow.

One common way to balance the scales is to adapt the characters and styles, while only representing the original story in broad strokes, sometimes only keeping parts of the origin story. Most recent Comic Book movies follow this method.

See also: In Name Only for the more extreme New Blood cases, or They Changed It, Now It Sucks and Pandering to the Base for the more extreme Old Guard cases.

Unclassifiable

 * The Hitchhiker's Guide to the Galaxy has been in every major media type in the world. It started on the radio, then it was a series of novels, then a TV show, a text-based adventure game, a movie, a stage play, a comic book, a towel, it's been released on LP, CD, and cassette. About the only thing there isn't is a Hitchhiker's ballet. But every single re-release is different from all the others. Invariably, of course, people start to complain about the things that were added and the things that were left out, with nobody being able to say which is the definitive version or which version is pandering to whom.
 * You can be certain that Douglas Adams himself found that fact very funny.
 * "The book is, as the title suggests, a collection of all the radio scripts, as broadcast, and it is therefore the only example of one Hitchhiker publication accurately and consistently reflecting another. I feel a little uncomfortable with this -- which is why the introduction to that book was written after the final and definitive one you are now reading and, of course, flatly contradicts it."—Douglas Adams, The Ultimate Hitchhiker's Guide, Introduction, referring to a recently published book of the complete scripts of the radio version
 * This got to the point where, when asked exactly how much material was going into the film version—would it be closer to the radio series or the books? Would it collect the whole story or just the first installment?--Adams answered that the film would "directly contradict only the first book."
 * How can you not mention the H2G2 towel?


 * Dungeons & Dragons the movie: Suffered severely from conflicting ideas that they wanted to attract the Dungeons and Dragons fanbase and at the same time alienate themselves from them for fear of being associated with "losers." As a result the movie was written by somebody who had never played the game, and the movie has pretty much lip service to the game and nothing else. A token, 5'4" dwarf, clerical magic being only accessible to elves, and Beholders that don't take advantage of the fact that they can look in all directions at once are just a few of the conflicts.
 * Underdog: Instead of being about a shoe-shine boy in a city of anthropomorphs, it's about a pet talking dog with Green Rocks.
 * The Super Mario Bros movie: It had plumbers, mushrooms (sorta), and a dinosaur, but other than that had nothing to do with the games. The bob-omb was pretty much its selling point.
 * Double Dragon: Both the cartoon and the movie took the Double Dragon legends in different directions. The movie made it a post-apocalyptic gang-war for a mystical medallion, whereas the cartoon turned Billy and Jimmy into ninja super heroes. Both were entertaining, but had little to do with the video games.
 * The comic mini-series (released by Marvel) split the difference; making Billy and Jimmy twin super-hero ninjas powered by a mystical statue. It also featured a So Bad It's Good extended cameo by
 * Night of Dark Shadows came out in 1971 and, while Dark Shadows, the television series it was based on, had only recently gone off the air, the plot and characters bore little or no resemblance to anything on the show (though arguably, what with some of the same actors from the show, and some of them actually portraying characters who happened to share names with characters from the series, there were recognizable parts for fans of the series. At best, it's a part of an alternate continuity with the earlier film House of Dark Shadows.)

Examples of balanced scales

 * 2007's Transformers Live Action Adaptation: Majorly re-wrote the storyline, bringing the US military in and making it easier to follow, while giving enough in-jokes and old quotes to keep the old fans happy. And Peter Cullen to pack them in the aisles in the first place.
 * And then there's Transformers Animated, which brought a new art style to the cartoon and placeed more emphasis on human supervillains to keep the Decepticons from looking ineffective, but won over a lot of converts in short order via strong writing and good use of the Mythology Gag.
 * V for Vendetta probably stands about in the middle here. It updated the political context and generally made it a bit more film-y (stronger female protagonist, more action scenes, less moral ambiguity), while keeping a lot of dialogue, visuals and themes from the comic.
 * Arguably, the most recent Radiohead albums have been trying to strike this sort of balance; In Rainbows successfully, Hail to the Thief perhaps less so.
 * X-Men: Evolution brought in a new art style and a completely new set of storylines while keeping as many old characters as they could. Their main new character, Spyke, failed testing and was written out (and a version of him was even executed by Wolverine in the unrelated X3 in a cool, but one-sided fight).
 * The original animated series also balanced quite well, even keeping some of the original storylines and adapting them to the format of the show.
 * Similarly, Marvel's Ultimate series is an attempt to bring casual and new fans into the fold by recreating their most popular works (Spider-Man, X-Men, Fantastic Four, and The Avengers) from the ground up. Although almost all villains and heroes are extremely familiar, they've all received major make-overs and have had their backstories retooled and modernized. In one of their most controversial points, they've removed Peter Parker's job as a photojournalist and made him a webjockey instead.
 * Well, when you put it that way, it sounds like it fits, even if the pun hurts.
 * The writers of the new Doctor Who are walking this tightrope very well, especially when you consider that they have a damn near Unpleasable Fanbase sometimes.
 * Serenity tried to present a self-contained story, and enough back history on the Firefly verse to be accessible to newbies, with enough nods to the series to please the hardcores. Ultimately, though, the amount of people that even knew what Firefly was, much less get interested enough to go see it, was just a little bit low.
 * The Iron Man movie is another strong example of this process done successfully.
 * Fanboys and regular moviegoers alike sure seem to be enjoying the Dark Knight Trilogy. Note that regular folks reacted to Batman Begins being made with "Batman? With the rubber nipples and terrible, campy villains? Why are you going back to that again?" and fanboys reacted to Heath Ledger being cast as The Joker in The Dark Knight with "That Brokeback prettyboy as the Joker? This is gonna SUCK!". Note further that both sides have since been forced to eat their own words in dramatic fashion.
 * The Mortal Kombat movie was enjoyed by the fans for being a faithful adaptation and moviegoers and critics enjoyed it for being a coherent action movie.
 * The South Park movie pretty much entirely makes sense if one hasn't seen the show, while still serving as a good episode of it. It's arguably better if you haven't seen the show, because Kenny's death actually seems to bear significance.
 * The new Star Trek movie seems, to a neutral outside observer, to be pretty balanced - perfectly comprehensible to a newbie, with enough Shout Outs to the Prime 'verse to satisfy even the most die-hard Trekkie. Within the fandom itself, it is either a wonderful and necessary revitalization of the franchise or a travesty that has ruined Trek forever and brought a legion of godawful newbies down upon the heads of "real fans." Bad things happen when the opinions mix.
 * Magic: The Gathering, as of late. The power-creep has been pretty damn noticeable lately, which makes older players cringe, and the newer Yu-Gi-Oh!-influenced generation squeal; however, the bar-none best cards are still those from well over 10 years ago, and the costs of these cards, whether the originals or in special reprint sets & decks, can easily run 40 bucks for a playset (4), making "veteran" formats like Legacy a nightmare for newer players to compete in. Let's just say that Magic is "balanced" in that it manages to delight and piss off both sides equally.
 * House of Dark Shadows, the 1970 film based on the cult hit soap opera Dark Shadows, pretty much falls here. It was not only filmed and released while the series was still on the air, but actually retold one of the show's early story arcs, albeit with a "new" (though Word of God says this was the original plan) twist on the ending of said arc.

Examples of falling on the Old Guard side.

 * Flintstones the movie: Almost the entire movie was focusing on the comedy of turning the old visual gags into live action, while following a stretched-out Flintstones plot. And the less said about the second movie, the better.
 * What makes it especially old guard are the adult subplots and Parental Bonus material. This troper was surprised to see Fred being seduced by a woman who knew he was married. This kind of thing was common with cynical 90's updates of movies and series from more "innocent" decades. As if people were unaware of the missing themes just because those themes weren't present in movies and television.
 * Dragonlance, Dragons of Autumn Twilight: While this editor enjoyed the movie, he had the feeling that somebody who had neither played the game nor read the books wouldn't have been able to keep up.
 * The Simpsons Movie: Granted, the Simpsons' fan base is so large that they could get away with this entirely. Still it was packed with so many in-jokes that even long term fans were forgetting a lot of them. Of course, the first thing the movie did was draw attention to the fact that it is virtually a giant Simpsons episode, so they probably knew that.
 * Sin City: Whether it works for it or against it is up to debate, but the movie religiously follows the comics (except when it comes to displaying nudity), to the point where the comics are literally used as storyboards.
 * The only nudity they cut was some male nudity (which was tried, and then removed, when they realized that it was drawing too much audience attention away from the important shit going on) and Nancy Callahan, which Alba refused to do, which is of course a valid artistic and personal choice.
 * Also Miho's nudity, which leads to the rather silly sight of the movie version jumping into the tar pit with clothes on. Also, Alba may have made a valid choice, yet it does seem absurd when her character is a stripper.
 * This Troper recalls reading an interview where Jessica Alba said that the director had actually given her the choice of whether she wanted to do nudity in Sin City or not, and that he almost convinced her to do it, but she ended up deciding not to. Sadly he has no idea where he read said interview now.
 * In the case of Sin City though, the novellas are short enough that they can be reproduced in their entirety, in-jokes intact, without actually having to remove the parts that make the in-jokes work. It's the best of both worlds: Fans appreciate that the references were left untouched, and newcomers appreciate that they actually get the references in question.
 * Star Wars novels are technically this; having mostly created the old guard in the first place, they continue to cater to them. Some of the more recent books however are being written with the concept of drawing more people in, and are avoiding making too much reference to the older books.
 * On the other hand, try telling a fan of The Thrawn Trilogy that the modern EU is catering to the old guard and prepare for either a rant or uncontrollable laughter.
 * That just shows they're fairly narrow in their consideration of what the "old guard" is. The Jedi Academy Trilogy, Tales of the Jedi series, Dark Empire series, and Young Jedi Knights were, among many others, also a part of the material that drew in the "old guard." That being said, the Republic Commando books, the New Jedi Order series, and most definitely Knights of the Old Republic games were clearly designed with the intention of drawing in new fans.
 * Watchmen pretty much is in the same situation as Sin City, except instead they had to cut and compress more content for time (some re-instated in DVD), didn't keep the visual style (although keeping most of the framing intact), and deciding this time to keep the male nudity.