There are a lot of cool concepts introduced over many episodes but at some point you feel like they could have done the whole series in 10, maybe even 8 episodes. I still very much enjoyed it, though there is not a lot of action.
I did not like it that much, it seemed more interesting in paper. While seeing I had the feeling that I was loosing other awesome series and I had to do a little effort to get to the sixth episode where I definitely stopped watching.
Kokkoku made a strong story until ep 12 which is the last ep. but the main reason they were afraid of time jumping and sending family back to real time becomes meaning less when the girl meet another girl and just used time jump together.
When youngest one in the family was in danger. And Elder I mean the grandfather of main character have to show his family Artifact which running in their family from long time.