There is only one word in the short sense. Incredible.
In the long sense I would start by focusing on the matter of three episodes, while I would wish for more so that I can get to know Mark (main character) further, I have never seen a show which so well tells a story is such little. Quality over quantity.
It is, again as a novelty, one of the few shows which made me shed a tear. Not because of what it is but what it represents.
This series is a masterpiece and I can only ask for more, with a further expanding plot, thank you.