So I saw the Hitchhiker's Guide movie...
And, well, it's a movie. It's not a great movie. It's not a terrible movie, either. It does feel a like it's misfiring - existing in the incredible state of Almost. I'm not sure what's wrong, but I know it's not what it really ought to be. It probably doesn't help that I've seen the TV series which consists of 7 roughly half-hour episodes and so had a bit more time to work with - but jmaynard has not seen the TV series[1] and has a similar assessment of the movie.
There are several places where a line is changed or a word dropped that means a joke is now not as effective. I won't point them out, there are enough places on-line that can likely do that. there is one bit that works while watching the movie (suspension of disbelief and all), but doesn't make sense when thinking about it late. Since it might just be a spoiler for someone, though I doubt it, I'll put it behind a cut. It's also not a very big deal.
In the sequence on Vogsphere where every time someone has a thought or idea they get hit in the face, Ford uses his towel to block the impact. But he doesn't seem to get hit in the face for thinking to do that. He gets hit (or almost hit) when he announces that he has an idea. This suggests that you can have thoughts and ideas as long as you don't tell anyone about them. But that doesn't work. If silence was protection, the run across the sands would have been just a run across the sands, not a run across the sands while getting hit in the face every couple steps.
Is it nitpicking? Probably.
[1] Something I hope to rectify sometime soon, since there is a DVD of the series out.