Speaking of just one joke, casting the wearily epicene Alan Rickman as the voice of the depressive robot Marvin (embodied by Warwick Davis with a huge, round, featureless silver head) must have seemed a slam-dunk. But that joke gets old more quickly than Rockwell's. When his lines fall flat, it's not bad, exactly—just, like Marvin, kind of sad.
Hitchhiker's is running out of fuel when Bill Nighy putters onto the screen like a modest Obi-Wan Kenobi. As Slartibartfast, he designs worlds instead of knocking them down, and he's the airiest Creator imaginable, with eyes at once enchanted and world-weary, and with that snorty little laugh (a Nighy trademark) for punctuation. Nighy's rueful grace makes him—not Arthur—the ideal mascot for this movie. When he says his favorite thing is designing "the fiddly bits" around fjords, the illogic of the universe seems blessed, and The Hitchhiker's Guide to the Galaxy is actually transporting.