I give it 6 because despite the ridiculous characters, this series still urge my curiosity and make me watch it till the end.
The series don't really have a meaningful new story (since we already grasp the story about the sun and everything from Into The Night). I just finished it and I can't recall a meaningful conflict, all I remember is the stupidity of the characters and unnecessary arguments here and there. We definitely can understand that everyone who's stuck in such apocalyptic situation won't be able to think clearly, but dang, the characters refused to listen to each other and it pissed me off, a lot. I tried to be neutral but i have to admit on the last several episodes, the scientist group are getting more annoying. For those who hates the submarines group in the first few episode and drop the show, i advice you to try finish the show and see how messed up the scientist group is. They're supposed to be smart but they refused to listen to other possibilities just because of what? Loyalty? They're too naive. It's okay to have several people in the group being that dumb, but the whole group? Come on. They also blamed everything on the submarine groups while most of "bad thing" that happened were mostly at their fault. Some people in the submarines group are annoying too, but at least they still have some logical people there, who's willing to listen to others.
So yeah, several "accidents" in the story can be solved, if only the scientist and the submarines willing to communicate with each others. But then again, we won't have stories if all of them are that smart. And maybe that's what the writers want? To make us frustrated? If that's the purpose, then good job on that.
The only think that push me to finish this was my curiosity, will the characters stay stubborn till the end, or there will be some character development? The answer lies in the last 20 minutes lmao. That's when they realised their stupidity, and that's when we get a glimpse of "new plot" for the next season/sequel. On the next sequel (which I guess the casts will be the mix between Yakamoz casts and Into The Night casts) i guess they'll finally start to figured things out together in more reasonable way.