I enjoyed the anime and that's all there is to it. Is the ending poorly executed? Of course.
I was trying to make light of it with my last post, if you couldn't tell. ;P But it's what you come to expect from short series like this, they
rarely have good endings,
rarely. The issue was the writers bit off more than they could chew by giving us such a build up to a fantastic dystopian society/scifi plot and only having one episode left to finish everything up. Had this been a 24 episode series, it would've been leagues better. But they just had to work with what they had. And they did a pretty good job. None of the episodes seemed pointless or like a waste of time. They just had too much content, for too little time.
I have to say I loved No.6, bull ending and all. I started watching it for the promise of an awesome plot, but the development of Nezumi and Shion's relationship was also surprisingly enjoyable to watch. In my opinion, a crap ending doesn't make a until-that-point amazing anime bad. I'm not going to get so caught up in my opinion towards the ending that I'm going to disregard everything else I thought about the series.
Seems like the general consensus among 'journalists'/reviewers as well;
REVIEW 1 REWIEW 2 REVIEW 3 REVIEW 4