In a way, I found Hitchhiker's to be quite frustrating to play because it relied on just way too many problem solving scenarios, but not in a fun or intuitive way as with other Infocom games. And as with many of Steve Meretzky's games, there were plenty of ways to die! Having Douglas Adam's novel as a reference guide didn't do much in the way of helping me progress that far at all.
While I did enjoy the Adams's British sense of humor (or humour) sprinkled throughout, I just remember being endlessly stuck and stuck and stuck in every new situation. In the end, I found the game a bit pointless in retrospect, as the whole point was to simply collect EVERYTHING otherwise you'd be in a no-win situation at the conclusion.
This was one of Infocom's more (most?) difficult "standard level" adventures. I never understood why they charged you more in $5 increments for the "advanced" and "expert" levels, but I think they made it "standard" for Hitchhiker's so it would have a broader appeal and sell more. Which it did.
A funny sidenote: my friend didn't know what rigor mortis meant ("...you're dead and should be concentrating on developing a good firm rigor mortis"), so he thought the game was giving us a valuable clue for the next go-around. So when typed "develop rigor mortis" in a later session, the game of course didn't recognize any of the words. :)