Episode 7 was worse. But after that, it improved a lot.
Awesome Music: The use and abuse of Dvoøák's Symphony No. 9, which coincidentally (or not) is also titled "From the New World".
While the show doesn't have an official opening theme, episodes 1-7 opens with this track. And boy, is it simultaneously terrifying and glorious to listen to.
Best Known for the Fanservice: Gets more attention for the same-sex romances than for the dystopian psychological horror that is the focus of the plot.
Big-Lipped Alligator Moment: The hallucination (?) of a boy turning into a False Minoshiro in episode 6 came completely out of the left field and was never explained.
Broken Base: Satoru's relationship with Shun in Episode 8 is a rather unfortunate example of this. Many viewed their relationship as heartwarming and were driven to tears when Shun ends the relationship just before he transforms into a Gouma. Some however were disgusted by this development, to the point of dropping the show altogether.
The show's decision to keep Satoru's and Saki's sex scene off-screen is quickly becoming a point of contention for fans who read the novel first and those still butt-hurt by Episode 8. Like TV Asahi would really show it.
Starting with episode 18, some fans have been complaining about the way the anime seems to be downplaying the Saki/Satoru relationship while placing more emphasis on Maria posthumously, via Saki's memories/imagination/visions of her.
For example, the novel has Saki realize that Satoru is the most important person to her. She later reveals to Satoru that she would like to have a child with him, and build the future together. The anime completely cuts this out.
Complete Monster: The boy referred to as "K" is a flashback character, whose tale warns society to not allow a person's psychic abilities to go unchecked. Pleas by his teacher to address his sociopathic tendencies ignored, K impulsively decided to attack everyone in sight, slaughtering any he could find in his school and then the whole village, the death toll reaching one thousand. Different from others in that his psychic abilities would not kill him when he attacked other humans, K delighted in massacring helpless people.
Creator's Pet: Maria in the anime adaptation. It's obvious that she is A-1 Pictures' favorite character, as she gets loads of screen-time (even after her death) and much more emphasis than in the original novel. Given that it comes at the cost of development toward Saki's and Satoru's relationship in the third story arc, quite a few fans are not impressed.
Part of it also likely stems from the double standard surrounding the popularity of Saki and Maria's romance as opposed to Satoru and Shun's romance. Satoru and Shun are only together for a single episode in the anime (though to be fair the relationship gets brought up a few times after), and aren't even a couple in the manga, while Maria and Saki kiss on screen several times and have implied sex.
Darkness-Induced Audience Apathy: By the end of the series, its hard to sympathize with either the human or the monster rat societies, as both have committed some truly horrible things in the name of neccessity. This makes it ultimately hard to root for anyone, especially the human main characters, as at least the monster rats seem like the underdogs.
To be fair, that's pretty much the point. The utopia of the series' beginning has been deconstructed.
Ensemble Dark Horse: A Four-Star Badasswho eliminates the Ground Spiders and later saves Saki and her friends from being turned in to the Ethics Committee, Kiromaru has established himself as this to viewers.
Despite being the head of the Ethics Committee, Satoru's grandmother Asahina Tomiko has earned this status thanks to her kind-heartedness with Saki and her willingness to tell her the truth about Akki and Gouma. The fact that she remains physically attractive never hurts either.
Esoteric Happy Ending: Yes, Satoru and Saki may be Happily Married and expecting a child, but Maria, Mamoru, and Shun are dead, the war between the Monster Rats and humanity has killed many from both sides, Squealer was subjected to a Fate Worse than Death so horrible that Saki Mercy Killed him out of pity, and Satoru could possibly have broken from learning the awful truth about the Monster Rats. Despite many residents of Kamisu 66 being killed, it's not clear that humanity will be moving toward the better, or even that they were humbled by Yakomaru's attacks.
The children (most specifically, Satoru) and Rijin the monk all show a disturbing tendency to pick the violent solution whenever they come across a conflict, as long as they aren't fighting against actual humans. It pretty plainly shows that for all the conditioning they go through, the PK-users are still prone of highly destructive behaviour, only barely kept in check by the social and genetic conditioning.
It turns out that the Sacred Barrier is actually meant to psychologically condition people to associate the outside world with the dark depths of their subconscious mind, so the entire world outside the protected areas is constantly being ravaged by the uncontrollable thoughts and emotions of the psychically talented people. Think of the Bakenezumi and how they probably used to be ordinary people.
Maria and Mamoru were murdered by Yakomaru nearly as soon as Maria gave birth to her child. Imagine the two being led into a false sense of security, before having their child and their lives brutally torn away from them the minute that little one finally enters the world. Then, if that wasn't already horrible enough, what sort of child rearing did that kid have to endure that would turn him into an absolutely Ax-Crazy, homicidal twelve year old?
Germans Love David Hasselhoff: You know a show has fans overseas when they start a movement pressing a licensing company to translate and publish the original novels in the US, UK, and Canada.
Saki experienced some cutie breakage from learning the truth behind her society, gets put into unwanted danger in all of the arcs, loses many, many friends and loved ones over the course of the story up to, and including four of her friends, two of whom were Love Interests, and then both of her parents, nearly gets killed loads of times (from many different sources mind you), witnesses a comrade get killed saving her before her very eyes, is forced to indirectly kill the homicidal child of two of her close friends, and then learns the Awful Truth about the Bakenezumi. She was always this close to crossing the Despair Event Horizon and breaks down crying several times in the story, but instead of becoming a Broken Bird like in most cases, her experiences instead make her grow stronger within each arc. Thank goodness she earns her happy ending.
Maria, was forced to leave her life in the village after the Board of Education decides to dispose of Mamoru and she chooses to run away with him to live a life with him in the wilderness to protect him. Her letter to Saki drives this point home.
Any moral props Yakomaru might have had left go out the window in Episode 21 when the Akki's identity is revealed. Combined with Tomiko's findings of the remains, it becomes crystal clear that he murdered Maria and Mamoru nearly as soon as she gave birth to her child. One can only imagine how he gave the two a false sense of security, before stripping both their child and their lives away from them the minute that little one finally enters the world. If that wasn't already reprehensible enough, he raises the kid and turns him into a horrifyingly sadistic madwoman. In addition to kidnapping the other babies in the nursery so he can do the same to them.
Human society as a whole is revealed to have crossed this in the past in Episode 25. As Satoru shares his discovery that Bakenezumi have 23 chromosomes (exactly the same as human beings) with Saki, he then reveals who the Bakenezumi really are. Remember the hunter-gatherers and the commoners who did NOT have PK powers? Yeah, it turns out that when Death Feedback was introduced, those with PK suddenly viewed those without PK as threats to their authority since they can't harm thanks to Death Feedback. So what do they do about it? They forcibly deformed and transformed those without PK by inserting naked molerat genes into their DNA. The transformation that ensued was so severe,it reached the point where killing the deformed PK-less people would not trigger Death Feedback. After learning this, you will probably find it much more easy to be sympathetic to Squealer. The worst part is that most humans don't even know this since the ones in charge kept it a secret.
In episode 15, what's done to the Queen is just as bad, if not even worse.
In episode 22, while travelling through the underground of what's left of Tokyo, Saki and the rest of her current group are forced to walk though an enormous pile of maggot-ridden fecal matter. Saki herself finds it completely disgusting!
Rooting for the Empire: Some fans sympathize with Yakomaru, since his race has been enslaved and treated like dirt by the humans.
The Bakenezumi...sometimes...It depends on your thoughts on naked mole-rats. And dark grey morality.
The normal Minoshiro has a big head, large eyes and stubby little limbs, but also gelatin-like skin and no proper mouth. The Minoshiro-modoki, on the other hand does away with most of the cute traits, instead possessing an elongated body with dignified proportions, but also the same grotesque elements as the normal Minoshiro. YMMV, ofcourse.
Villain Has a Point: When Saki and Satoru confront Yakomaru over his reasons for revolting against humanity, Yakomaru points out that the Bakenezumi are intelligent beings that have essentially been enslaved by the telepathically gifted human ruling class, and that he was only fighting to secure freedom for his people.
Win Back the Crowd: A meta-example for Satoru's seiyuu Yuuki Kaji. While Kaji's career was never in danger, he DID attract a lot of criticism from anime viewers for his performances as the leads in Guilty Crown and Accel World. Kaji's tour de force portrayal of Satoru, however, recified his career for the fans (or at least, is well on his way to being redeemed).
The Woobie: EVERYONE from Group 1, most notably Mamoru.
Woobie, Destroyer of Worlds: Shun, post Karma Demon transformation. See Tearjerker for more info. Also, Izumi Kutegawa, the last recorded Gouma from Tomiko's story, for her very, very sad backstory. The Destroyer of Worlds part comes in not because they want to, but because their condition as Gouma, whose growing powers go out of control, force them to.