I waited until i had watched all four episodes before writing a comment here.
Like any first series it suffers from uncertain characterisations and exposition.
First the negatives:
1. The photography - the excessive closeups and blurred backgrounds just serve to distance the audience. This style is a fad at the moment and not one I like.
2. there was definitely a problem with the sound. The actors seem to have been miked too closely resulting in a muffled unclear sound that was hard to understand much of the time. The sound needs to be re-equalised to push out the voice component.
3. the production design was weird. The police offices were like a lost set from Star Trek™.
4. the plot was ultimately too easy and telegraphed too obviously. I guessed who and why well before the end of the first episode.
BUT despite this some of this series was gripping. Especially the last episode. The performances finally were allowed to show through. And it is for this episode that I gave the series an 8 out of 10.
I hope there is a second series. The show has promise. None of the issues with the first series are unfixable. Ann Cleeves is a brilliant writer and it shows in parts of The Long Call.