These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Complete Monster: Sadist Teacher Shidou first shows he's a man to fear when, during a zombie attack, when a student he's guiding twists his ankle and begs Shidou for help. Shidou's response was to kick him in the face, and gloating over the poor kid's impending death and his own survival by telling that the new world had no place for people that weak. Then he uses his position as a teacher to get himself elected leader of the surviving group. Shidou sets out to make himself a cult leader, promoting sexual activity amongst the kids to make them loyal to Shidou. When a student doesn't like the action going on in the "orgybus" and asks if he can just be dropped off at his house to see if his family is ok. Shidou and his group, who are at this point a cult, decide that the best way to grant his wish is to throw him out of the bus and let him get eaten. In a Zombie Apocalypse, Shidou stands out as more evil and vile than any walking corpse.
Crosses the Line Twice: Accidentally shooting an infected woman in the breasts? Fan Disservice. Accidentally shooting an infected woman in the breasts, and then accusing the offending bullet of sexism? Hilarious!
Towards the end of Episode 5, Shizuka refers to Rika as her girlfriend, followed by an Imagine Spot of Shizuka in a maid outfit keeping the apartment clean for her. Furthermore, she also fantasizes about Rika (actually Saya) under the influence of the hallucinogenic smoke in the OVA. When the smoke wears off later, we see the two nude and snuggling with each other.
Mis-blamed: Some people who watched the anime but haven't read the manga complained that Madhouse inserted sexual fanservice, but some of it was taken directly from the manga. Though some of the more infamous instances of fanservice (such as Saeko's "boob matrix" scene) are exclusive to the anime.
As the High School is overrun by zombies, two BFFs proclaim their everlasting friendship right before one gets grabbed and the other turns on her and kicks her to her death, right before getting chomped on herself.
The household that kills Alice's father and ignores her.
When Rei says that Shidou isn't to be trusted, you wonder why, until a couple pages later when he kicks a student in the face when he twists his ankle and asks for help.
Shidou's father himself crosses the MEH when he deliberately has all evidence of his corruption destroyed or otherwise disposed of during an investigation into his activities, as Rei implies when she states that her father found absolutely nothing incriminating about the bastard.
Oh, and as if Shidou's willingness to harm his own students (and even murder them; see Complete Monster) wasn't bad enough, he had to go and get Rei's mother ostracized. Yes, his family finally shamed Rei's entire family. And That's Terrible. Perhaps Rei should've crossed the MEH (see below); it's a wonder the main party found Mrs. Miyamoto alive and not infected after being shut out by her own neighbors following a simple shopping trip.
The protagonists themselves have acknowledged they may cross the line as far as old human society is concerned. So far, two of them think they already have crossed the line: Takashi believes he crossed the MEH by killing his best friend partly out of jealousy over Rei and doesn't regret leaving someone (a violent nutjob, granted, but still a living human) as live bait for the zombies for attempting to kill him and take Rei, and Saeko claims to have crossed the line long ago, when a man attempted to rape her and she defended herself, but enjoyed it and continued hitting him even after he was no longer a threat. Rei comes very close to the Moral Event Horizon when she's given an opportunity to kill Shidou as revenge for rigging her grades over her father's involvement in the investigation of Shidou's father's corruption (an act that can be considered Shidou's earliest candidate for Moral Event Horizon, by the way—both Rei and Mr. Takagi definitely think it's bad enough to warrant a summary execution). However, she decides he's Not Worth Killing, thus averting this trope. Perhaps she should've killed him (and potentially crossed the MEH) then and there, considering what the fuck almost happened to her mother shortly after Shidou recovered from the subsequent ambush on his lot by "them".
MST3K Mantra: The curious interaction between gritty realism and gratuitous, over-the-top Rule of Cool makes this the best reaction to several aspects of the show, especially the matter of zombie navigation. The fanservice is another point of contention to deal with if one is to enjoy the series.
Narm: The fanservice reaches ridiculous levels at times.
Takashi grabbing Saeko's boob during his rousing speech at the end of Episode 9 becomes this, which seems strange since there was no apparent reason for it. Not mention, he was damn near crushing it. It's a wonder Saeko wasn't in pain. Instead, she seemed to get off on it.
Rei due to a combination of being on the wrong end of Die for Our Ship treatment from Saeko x Takashi fans as well being an occasional Faux Action Girl and for grieving over her boyfriend's death. Many of her haters regularly bash her for accusing Takashi of wanting to kill her boyfriend out of jealousy something he makes no attempt to deny and even admits to himself that she may be right. That she apologizes for it and only said in it in the heat of the moment contributes to her Broken Base.
Any fanservice having to do with the brainwashed kids or the zombies.
From the OVA, the revelation that Takashi had hallucinations of the group's women suggests that he had scored with or tried to score with a zombie rather than Saeko or Rei.
Suspiciously Similar Song: The anime's first episode features a track mimicking "In the house, in a heartbeat" from 28 Days Later. Episode 4 features another track mimicking "Abide by Me" from the same movie.
And a zombie resembling Bae Yong-Joon being sniped in the head. Why is this controversial? Because the sniper noted that he was an actor and derisively referred to him as a "scumbag" right before pulling the trigger. Korean viewers of the show were not amused.
What an Idiot: Okay Mr. nihilisticmall survivor, you claim to be such a huge zombie fan and yet charge into a group of zombies while pathetically flailing a knife about, when it's been established that any melee weapon shorter than an arm's length will only let them get within biting range? All for the sake of going out like a badass? Not to mention that your stab wound wasn't even critical and the zombies could have easily been avoided? Enjoy your undignified, lameass death.
What Do You Mean, It's Not Political?: Saya's family and their supporters are a group of uyoku dantai-militant, traditionalist Japanese ultra-nationalists with an eye on reclaiming lost territory and historical revisionism. It's considered politically incorrect in Japan to forward ideas like that, much less on a Fanservice show. Simultaneously, the left wing protestors and survivors in the camp act like idiots. It's not clear if this is the authors personal opinion or dramatic embellishment, but his older works like USA vs. Japan 2025 and an alternate history where Japan is divided Korea-style after World War II clearly state that he is more sympathetic to the Japanese right, even though not necessarily belong to them. The ultra-nationalists were censored in the anime as their views are considered politically incorrect.
The Woobie: Asami gets belittled and ignored by the mall survivors, found that her instructor got zombified while looking for help, has a Heroic BSOD, and is later Mercy Killed after being trapped while rescuing the person that necessitated escape.
Woolseyism: When the gang shacks up at Shizuka's friend's apartment (who is not there), they find entire closets full of guns. Takashi mutters "Who is this chick, Sarah fucking Palin?"