My kind of silly.
I'd known the story for many years, but didn't realise it was written in the 70s (or "nearly 80s"). My best knowledge of it was the movie with Martin Freeman in 2005 … which, didn't quite live up to my expectation round the hype.
The book I found to be better (than the film - sorry purists - I know I shouldn't compare!), though I couldn't stop hearing Alan Rickman's voice as Marvin.
I did sort of feel like nothing actually happened in the book. It was an adventure, but I think I missed the character arcs - or… I wasn't sure where to look!
Overall, good, funny and properly silly.