2.4 stars. Lukewarm tea. There are some amicable enough elements - Fry is appropriately sage and wry as the voice of the Guide and Bill Bailey makes a perfectly flummoxed whale, but the whole thing feels smooth and airless, missing the fact that what makes the radio show, novels, IF game and TV series so effective are the very same things that make them awkward and unruly. In short, not enough digressions.
The unique source material makes this a above average science fiction comedy with excellent ensemble. The problem is that the film is too short and lacks many details and favorite moments for fans, but I liked it. Hell, even my brother who despises science fiction has said he liked it.