Living in Czechoslovakia/The Czech Republic in the 1990s so much of this rang true as far as life in this part of the world at that time. I would say they got the architecture, decore, fashion, and the way people behaved and communicated down very well, it was so much like what was still around and what I was told about (though in a different country), I saw the remenents of it, this, I would guess, was was it was really like. It was also shot and acted very well.
As far as the story goes, I don't get how so many reviewers complain of being confused. There were the usual multiple threads, suspects, and gaps in the story for the viewers or protagonists to fill in. People should watch a little more closely and accept the fact that not everything is laid out for you and that things tie up, or sometimes don't, in the end.
In general there was nothing flashy, the impressive thing was the everyday detail and convincing human aspect, like I said, they kept it simple in that sense, and got it right.
I would hope there will be another series.