S2 dosent have a "bad" ending it just could have been better. suou was put on a fake earth created by shion with the memories of all the people who had had ME used on them.
they dont come out and say it but since the "moon" is in "space" or whatever the fake sky is, she can maintain her memories there since its surrounded by meteors.
at least thats how i understood it.
the only thing that made no sense to me was the boy at the end with the white hair ho killed the CIA team. im guessing hes izanagi, but he could be something else entirely.
hopefully S3 will answer some questions kinda like gaiden made S2 much better.
id laugh if suou comes back after finding out where she is. that kinda would ruin it for me if they didnt do it right.