Sadly, Mr. Adams expired in 2001, but not before completing the first draft of the film's screenplay. We can reasonably surmise that the completed cinematic version bears some resemblance to what Adams saw in his delightfully damaged brain.
In all honestly, I'm not sure that the film version will greatly expand the Hitchhiker's cult. It's hard to imagine a lot of newcomers being drawn to the film's surrealistically silly brand of sci-fi. On the other hand, most longtime fans (yours truly included) will be more or less pleased to see the book's characters and situations sprung to absurd life.
The book was envisioned once before, of course, in the 1981 BBC mini-series. While the feature-length Hitchhiker's movie has a modest budget in Hollywood terms, it's still leagues ahead of the poverty-row TV series.
It's important to note that Adams' work has lived a number of lives, each one largely reworked by Adams himself. The differences between the radio series, the book, the sequels, the TV show and the movie are notable. Those looking for strict continuity are sailing through the wrong universe here.
As a film, The Hitchhiker's Guide to the Galaxy sticks to the same basic framework of its predecessors. It takes plenty of time out for assorted side travels, however. I still can't imagine this upsetting longtime Hitchhiker fans since–as previously stated–Adams liked revamping his ideas from time to time anyway. The end result is that even those who've memorized every line in Hitchhiker's (and there are plenty who have) will find plenty of new treats awaiting them in the movie theater.
That isn't to say that this new adaptation is perfect. As noted previously, if you're not already an Adams acolyte, you may think this rickety rocket ride is nothing more than a goofy amalgam of “Doctor Who” and “Monty Python.” (Which, in some ways, it is.) The rapid-fire and largely nonsensical story line also isn't the type to suck newcomers in. (The neophyte sitting behind me kept wondering what the deal with all the towels was.)
Basically, we've got terminally nervous Englishman Arthur Dent (Martin Freeman from “The Office”) being rescued from Earth by his best friend (and secret extraterrestrial) Ford Prefect (rapper/actor Mos Def) mere moments before its complete demolition. The duo are eventually picked up by the renegade President of the Universe Zaphod Beeblebrox (an unhinged Sam Rockwell) and a cute space babe named Trillian (Zooey Deschanel). From there, our heroes (along with a clinically depressed robot) go looking for the meaning of life, the universe and everything with the able assistance of the wondrous guidebook mentioned in the title.
Naturally, a lot of Adams' book has been excised for the sake of brevity. This is difficult, as the strength of Adams' humor lies in his ability to over-explain a joke. Adams never wrote punch lines. But he explained jokes for pages on end. The more he explained things, the funnier they got. Such verbose digressions are hard to pull off in a film. Most jokes end up seriously trimmed. Thankfully, a few of the lengthy “Hitchhiker's Guide” entries remain in the form of animated interludes. (Stick around through the end credits for one of the best.)
With so much cut, some observers may find it odd that items have actually been added. A subplot involving a love triangle between Arthur, Trillian and Zaphod is clearly shoehorned in to give the story some dramatic arc. It works fine. Another subplot, introducing John Malkovich as the alien religious leader Humma Kavula, starts out promisingly, but drops out of sight by the film's end. Ah well–Adams was always more interested in wacky situations than linear plots anyway.
All in all, the cast is spot on. Freeman is a great choice to play perpetually bathrobed Arthur. Mos Def (still bringing dignity to the term rapper/actor) cuts a fine figure as Ford. Rockwell gives it his all, Deschanel is disarmingly cute and Alan Rickman provides the perfect glum voice for Marvin the Paranoid Android.
In the summer of Star Wars, there's very little chance that The Hitchhiker's Guide to the Galaxy is going to be the season's memorable sci-fi epic. Still, it's an amusing, anarchy-filled diversion. See it and, above all, don't panic.