Ugh... I just. I'm so disappointed...
I was there 100% for the first 4-5 episodes, but then it was a steep and steady decline to the end. The final episode was the epitome of everything that let the show down. I'm struggling where to even begin with it, there's just so many inconsistencies in plot devices and character behaviour, and there's no need for it.
It would have been much better if it just focussed on a couple of things rather than try everything. It's a fantastic idea, some themes and questions it raises utterly fascinated me, but it became shallow and rotted away. It's like they got a sci-fi visionary to come up with a fascinating scenario but then dropped them for a JJ Abrams type who very quickly drained all its lasting appeal for the sake of Lost/GoT-esque twists and turns.