I haven't seen the first series and my review is based completely on series 2.
I think it became clear about halfway through the series that the writers didn't know what they were doing and had no ending. For some reason I continued to watch in a kind of fascinated horror to see if the series would get any better. It didn't.
Characters were added halfway through the show who served no purpose ( especially the badly acted lesbian couple who were wanting a child) and about 75% of each episode seemed to be padding or red herrings.
I don't think many will be satisfied that so few storylines have been resolved . It might be possible that the makers will attempt a series 3. If they do I won't be watching.