So, I shall not put this as a 'must watch' programme, because the phrase is often overused.
I will definitely say that it is a 'should see'.
Without spoilers, I will say that there are some plot holes, but then there is the build up to the final episode.
I did like the fact that the character development is retrospective, and that continues right to the last seconds of the final episode.
There are layers upon layers, and at one point, I had convinced myself that I knew what the final twist would be....
Then the final twist caught me by surprise, and I really enjoyed that. It is a strange blend of secrets, coupled with some parallel storylines.
If I had any complaints, it should have had another episode or maybe two, just to flesh out the additional storylines, and fill the plot holes.
But, it is very well done, it is definitely worth seeing, and there is a commentary on the troubles of being human.