Whenever a film adaptation comes out, the same klaxons blare: the movie ruined the book! That's a load of fetid dingo's kidneys. Case in point, Douglas Adams wrote the Hitchhiker's Guide to the Galaxy for just about every available media - radio, books, stage, TV, video games and film.
Each version was adapted to suit the medium, rather than forcing the story to fit. He is the first, and so far only writer to do that for so many different formats, and Zarking Fardwarks, if he didn't do a hoopy job!
It's the nature of adaptations to alter a story for the chosen media, and as a veteran TV, radio and stage writer, Adams understood this. Here's a fan's guide to the Hitchhiker's Guide to the Galaxy's multiple formats.
Radio Plays: The listener's imagination has an unlimited budget
Although radio plays have all but disappeared in the States, across the pond audio dramas are still alive and well. Doctor Who stories featuring original cast members can continue to be told, without worry about changes in age or appearance. Perhaps more significantly to the matter at hand, the original cast and crew of the Hitchhiker's Guide are working on new recordings.
Now, it's true, these recordings lend themselves well to animation, but there are things you can do with radio that just can't be achieved any other way.
The Hitchhiker's story was originally presented on the radio, and the jokes were tailored for it. Zaphod Beeblebrox famously has two heads and three arms, but these facts were merely throwaway jokes. The gag here, is that listeners would have heard characters interacting with Zaphod casually up to this point, only to learn, matter-of-factly, that he'd had extra appendages the whole time. These gags often got extended by the actors themselves. Mark Wing-Davey, the original Zaphod, once gave Geoffrey McGivern, playing Ford Prefect, one too many high fives, suggesting he'd grown a fourth arm at some point.
These gags appear throughout the series, including the fun situation of Gargravarr, who has just as much vocal presence as any other character, but who has no body to speak of. The eerily, disembodied effect is left to the listener's imaginations to fill in.
Novels: Verbosity is your friend
Read this excerpt from the Life, the Universe and Everything (book three in the trilogy of five or six books):
"Why," said Trillian, "do you feel you have to destroy the Universe?"
She found it a little difficult talking into nothingness, with nothing on which to focus. Hactar obviously noticed this. He chuckled a ghostly chuckle.
"If it's going to be that sort of session," he said, "we may as well have the right sort of setting."
And now there materialized in front of them something new. It was the dim hazy image of a couch – a psychiatrist's couch. The leather with which it was upholstered was shiny and sumptuous, but again, it was only a trick of the light.
Around them, to complete the setting, was the hazy suggestion of wood-panelled walls. And then, on the couch, appeared the image of Hactar himself, and it was an eye-twisting image.
The couch looked normal size for a psychiatrist's couch – about five or six feet long.
The computer looked normal size for a black space-borne computer satellite – about a thousand miles across.
The illusion that the one was sitting on top of the other was the thing which made the eyes twist.
Now, imagine that on film. Go ahead. Try. Sure, an approximation could be accomplished, but there is no way the sheer scale and impossibility of this surreal image could ever be portrayed. And that's on purpose. By this point in the book series, Adams had pulled back on the radio commitments (though he always intended to return), and could let his keyboard run rampant with "visuals" that even the radio would have a hard time presenting.
Of course, after Adams passing his friends and colleagues got together and reworked the later Hitchhiker's stories into excellent radio plays, and while some changes worked well - such as clearing up some of the confusing plot contrivances of the fifth book, Mostly Harmless - some things were only meant for the printed page. Here is the radio version of that same scene, adapted by Dirk Maggs, who is working on the upcoming recording as well:
TRILLIAN: Er, Hactar, if the Universe interests you so much, why do you feel you have to destroy it?
HACTAR: Oh dear, perhaps a psychiatrist's couch would have served us better?
SOUND EFFECTS: SUSURRATION OF ATOMS RECONFIGURING.
ARTHUR: (Shifting in his seat) Oh. I think I preferred the sofa.
SOUND EFFECTS: SUSURRATION OF ATOMS RECONFIGURING.
ARTHUR: (continued) Thank you.
It's fun, but not quite the same, is it?
Adams also understood that stories change, and he wasn't above making minor and major changes to his own opus. The famous opening scene of the story, in which Arthur steadfastly (but impotently) protests the destruction of his home by Mr. Prosser and the town council, was drastically different in the radio version. In the original, it was Arthur himself who tricked Prosser into lying in the mud, something that seems uncharacteristically manipulative, based on Arthur's later actions. The book had Ford sweet talk Prosser down, and this has remained in all subsequent versions.
Stage: Play to your audience
While I've never read the script myself, Adams worked on a stage adaptation early on (though at least one script was adapted by Jonathan Petheridge). Scenes of standing around and talking or heavy narration were likely excised, but new scenes were added to take advantage of the fact that audiences could now react to the silliness of the story, and the actors could now react to the laughter of the audience.
The famous "Dish of the Day" scene was added for the stage, and infamously played on the TV series by future Doctor (and then-husband of TV Trillian, Sandra Dickinson), Peter Davison.
In the scene, the regular cast stop at an infinitely trendy restaurant and enjoy Ameglian Major Cow, "an animal that actually wanted to be eaten and was capable of saying so clearly and distinctly."
Again, the scene proved so popular, it stayed for most future versions.
Television: Visual gags help
As Hitchhiker's grew in popularity, and considering Adams then-current job as script editor of Doctor Who, it was only natural for Hitchhiker's to make the jump to the small screen. Douglas, of course, provided the scripts.
The series took advantage of the new medium, expanding visual gags like the Hitchiker's Guide entries - amazingly animated by Rod Lord - and adding new concepts, like the idea that a jump through hyperspace would cause a towel to move six feet, or the colorful Dentrassi Hagra biscuit, which had been lovingly prepared for Vogon pallets only.
It also helped that Simon Jones, the actor for whom Adams created Arthur Dent and who brought him to life on radio, was perfect for TV. Adams and Jones had worked together previously on a failed sketch comedy show, Out of the Trees.
In returning the story to a serialized format, as it had originally been presented on radio, Adams was able to tighten up the story somewhat more. This allowed events to flow much smoother and gags to be set up farther in advance. Sadly, BBC's TV budget in those days wasn't quite what it is today, and modern audiences might find all of the special effects a little aged.
Music: Disco robot
Feeding into and off of the property's popularity, Adams wasn't above getting into the disco scene. He and Marvin actor Stephen Moore worked on several cult-hit dance tunes staring everyone's (least?) favorite paranoid android.
The songs added new storylines, including Marvin's lackadaisical murder of some unnamed ship's captain and a female robot programmed for Marvin, but who is destined never to meet Marvin again. These bits could easily fit in between the stories as presented in other formats, but were only given life in song.
Video Games: Let the audience (believe they can) control the story
Then came the most fiendishly clever version of the story yet - the video game.
Together with Infocom creator Steve Meretzky, Adams created a version of the Hitchhiker's story that could be crafted by the audience themselves, while retaining the biting humor the series was known for. The text game was so hard that new players often died before leaving Arthur Dent's bedroom (the first scene in the game), and the trial-and-error needed to procure the Babel Fish - the biological universal translator needed to progress past the first section of the game - was so insanely annoying that Infocom offered t-shirts to any game who could prove they'd achieved it, proudly proclaiming to the world, "I got the Babel Fish!"
In this iteration of the story, players could stop a small dog from eating the microscopic space fleet (as it had in all other versions) and even hitch a ride on the fleet itself before traveling into Arthur's brain to manually remove his common sense. For the first time, audiences got a chance to see Trillian's first meeting with Arthur from her point of view, and experience what it is like to live life in Zaphod's heads.
Infocom also included "feelies," little manipulatives that players could use in the real world. Although they had no effect on the game, it was fun to actually see the orders for Earth's destruction or try on Zaphod's Peril Sensitive Sunglasses.
Film: Sometimes you just have to wrap it up
Finally, there is the much-lamented movie. While not the greatest addition to the Hitchhiker's multiverse, the 2005 movie was based on a screenplay Adams had written before his untimely total existence failure in 2001. Understanding the nature of cinema, Douglas Adams worked and reworked the story to tell a single story arc in 90 minutes. Here's an interview he did shortly after one of his last drafts:
I've hit a certain amount of difficulty over the years in explaining this in Hollywood. I'm often asked 'Yes, but what are his goals?' to which I can only respond, well, I think he'd just like all this to stop, really. It's been a hard sell. I rather miss David Vogel from the film process. He's the studio executive at Disney who was in charge of the project for a while, but has since departed. There was a big meeting at one time to discuss, amongst other things, Arthur's heroicness or lack of it. David suddenly asked me 'Does Arthur's presence in the proceedings make a difference to the way things turn out?' to which I said, slightly puzzled, 'Well, yes.' David smiled and said 'Good. Then he's a hero.'
Although the final version of the film shows clear non-Adamsean changes, the basic thrust is clear: Arthur leaves Earth, Arthur learns about the mysteries of Life, the Universe and Everything, Arthur comes to a grand realization. Adams also added new characters to the mix to help move the story along (and presumably prep it for a trilogy of some sort), including Galactic Vice President Questular and Humma Kavula.
The film, for all it's flaws, also had some good points that had nothing to do with Adams - although not matching their literary descriptions, the Vogons, the Heart of Gold and especially Marvin all seemed pitch perfect in design.
The take-way from all this is that different versions of stories should tell stories differently, and changes can and should be made for each medium. And that's the ultimate answer.