No.6 has a very good start but then starts to suffer. I don't know what went wrong but it is a shame. I very much enjoyed this but the story and direction just went downhill. I don't usually check manga but I had to with this one.
Love, sacrifice, mystery, acceptance would be the words if I had to describe this show. Orwell 1984 also comes to mind.
Art style and sounds were just fine. It was cute when it needed to be. Sometimes the animation was janky.
Characters Nezumi and Shion save this show for me. I was interested in their stories and how they are going to resolve their situation.
Unfortunately it falls short. Reading the manga is the right choice here or at least after you watch this go check the manga ending.