Pat289’s review published on Letterboxd:
Stephen Mangan is fun to watch as Dirk Gently but the rest of the cast seems so uninvested and lifeless in their performances. Maybe that was part of the joke (a quirky, lively main character paired with a rather bland supporting cast) but it just didn't work for me.
You can absolutely tell that the makers of this pilot are fans of the Dirk Gently books - there are numerous easter eggs and dialogue exchanges straight from the novel in here. But it is just not dynamic enough or even weird enough to represent Douglas Adams' creation properly. It just seems like a slower version of BBC's Sherlock.
All in all, this is an okay watch but nothing noteworthy or particularly memorable. I might give the rest of this series a try though, since it has only three other episodes.