A common and well-known problem, when adapting an IP from its original medium to another is to avoid alienating the fans by betraying the source material, intentionally or not.
Some stories simply don't 'translate' well to any other medium, while others will simply crash into impossible budget, production or artistic constraints on the new medium that didn't hinder the original, and will inevitably force compromises.
Nowadays, creators across platforms and genres are aware enough of the issue that many of them try to factor the potential for adaptation in their original production — this is especially true of written fiction, which is a difficult trade to make a living from by itself, but where a single movie deal over a readily written book can sometimes — literally — get one from rags to riches.
Whether factoring the limitations of a different medium when writing a novel does any good to literature is debatable, but it certainly can help ensure the filmic adaptation will be less likely to betray the original book.
What of videogames, then ?
While there is no shortage of insightful work about the peculiar challenges of interactive storytelling, and of the difficulty to port a story from a linear, author-at-the-wheel medium such as a novel or movie to a more freeform experience, most of the discussion usually revolves about the pitfalls of 'too much' freedom or control granted to the 'audience'… How can you stop people from taking powergaming shortcuts with your story, or from simply killing off the insufferable protagonist/love-interest/sidekick the first chance they get, and still keep them somewhat engaged in a game experience ? — yes, Harry Potter, I'm looking at you.
It seems however that the converse issue of coping with the restrictions imposed by limited interactivity gets less attention, or rather the question has been largely abandoned, whereas more interactivity used to be the obsession of gamemakers during the pre-and-early 3D era.
ChocoPuffs Online — the slasher game.
Are we so happy today with the completeness and perfect seamlessness of the physics and visual engines in our current 3D game worlds that the only thing that separates videogames from movies is strictly a matter of artistic choice ? Bluntly put: I think not.
Perversely, every improvement in graphics and physics in videogames only makes matters worse by raising our expectations about immersion, verisimilitude and interactivity freedom to heights that can't reasonably be met, short of reaching Matrix-esque simulationist quality.
Videogames versions of beloved franchises tend to prove generally about as reliable and faithful to the original IP as you can expect the similarly-themed breakfast cereal to be: Mrs Butterfly's Morning Surprise: now with raisins !
…OK, bad example, those would be kinda cool, actually.
Everybody wants to be a Jedi !
With sandbox-themed games being all the rage these days, new problems arise, and MMOs are a spectacularly unforgiving platform for adaptation of original material that hasn't been created with massively multiplayer in mind.
Star Wars Galaxies is possibly the uber-example of that: when your IP is beloved for its rich and colorful universe, yet your entire storyline is entirely focused on the respective and successive, all epically-scaled hero's journeys of a son, his antagonist father, and the father's own father figure (because he's an orphan, true story), things get hairy shortly after they fall in the hands of the enemy.
If spinoff novels, comic books, CRPGs and even tabletop RPG can take the time to plead a good case to the fans in favor of delving into other, previously undeveloped aspects of the Expanded Universe, thanks to the directive nature of the medium (or willful association for TT RPG), MMOs don't have that luxury, and the capacity of thousands of free-roaming players to collectively drag each other down and afar from playing the game as intended by design can't be overstated.
I'm pretty sure my class should be able to climb stairs…
Denying players their rightful heirloom as the putative unique son of the greatest king to ever roam the galaxy is only a side dish in the seven course meal piling up on the plate of the designer in the process of porting a story to a R-POW sandbox, however: the entrée comes in large helpings of game mechanics/engine limitations.
Source material, whether books or movies, doesn't just define the gameverse and backstory, it paints the spectrum of typical in-verse actions heroes can perform, beyond the mundane or within. If the videogame version even so much as brushes near any topical feature taken from the original IP, players brains will be primed to jump right into action, and if they can't because the game engine won't let them, much disappointment ensues.
The nature of a massive sandbox makes it extremely likely any given player will not brush near, but instead run into a great many such topical features, and the odds of disappointed expectations are proportionally heightened.
Not to bash on the Star Wars videogames franchise, as I have a long love story with many LucasArts titles, but having to run the long way around an open grass lawn to reach the handifriendly wheelchair ramp, simply because my friggin Jedi can't step over a 4" thick kerb edge kind of kills my Force-induced buzz.
Thus, fiction writing and MMOs have a contentious relationship. Backstory books and chronicle-type novelizations are powerful immersion devices and seamless tutorial tools, and can vicariously enhance the otherwise limited experience some players have of the gameverse, but they can also shine a searchlight on stuff that simply feels like it ought to be doable in game, yet isn't.
Twisting the record straight.
There is a simple way to avoid the clash between a sandbox MMO and its derivative products or supporting source material, and that's to design and write source material hand in hand.
Many designers use snippets of written fiction, or simply roleplay during brainstorming sessions to get a feel for how a given scene or situation coulda-oughta-shoulda play out in game. This makes perfect sense, and builds on the well-known effect having to explain your ideas to somebody has on your own understanding thereof. For mysterious reasons, this practice has not been given much credit in the industry, and is largely considered anecdotal, a personal trait or quirk of some individual designers rather than part of any formal method of sandbox game design.
If done early and soon, and if actually made a defining part of the design process, design by tales can be a very powerful tool for designers to maintain design consistency, craftily expose players to content they didn't yet realize existed, and shape players expectations about gameplay.
On the designer end, writing helps figure gameplay 'musts', to better prioritize and plan new features or changes, and can be a great source of inspiration for new content or design elements.
There's only one risk with fiction writing as a game design method: one may sometimes get carried away while jotting down a quick illustrative example…