Personally I think the show held it's world-building too close to it's chest for sake of creating mysteries only for that to backfire with many fans when the answers to those mysteries turned out to be neither surprising or interesting enough to warrant being strung along for that amount of time. It's similar to what happened for me with Danganronpa. You and Tokoya seem to have been enjoying this show far more than I have so I'm sure you feel differently.
Yes, it was incredibly disappointing.
I still haven't digested that. I could bear with any drama as long as it was sustained by some mysteries. Now the dynamic is different. Too much drama altogether. I wouldn't say it's badly done, some scenes were done well, and it was moving to a point. For example, there were scenes in that latest episode that I really enjoyed.
As my boyfriend said, it's TTGL gone wrong with the aliens. Those characters are teenagers, for the audience, doing stuff for adults, like being about to have a kid. It's a post-apocalyptic world, it will be the first normal born kid in years, but it's so wrong.
Older characters would have been better.
It would have allowed them to be a bit badass, which they really are not.
The most horrid part for me was Alpha's death. It felt useless, as if they simply needed to get rid of the character. Forced drama, really.
In any case, I really wanted the humans to be the bad guys, to have ruined earth by themselves. It would have made the show so much better. But no, humans are not evil, humans don't ruin the earth, it has to be someone else who did it >_> *sigh*