History YMMV / AllOfUsAreDead

* CompleteMonster: [[BarbaricBully Yoon Gwi-nam]], starting as a cruel bully who exploits, beats, and sexually humiliates his peers, [[DirtyCoward uses students as bait]] to escape zombies and murders his principal. After being bitten by the zombies, Gwi-nam becomes a [[EliteZombie hybrid]] who relentlessly hunts his enemy Lee Cheong-san and murders and tortures every student he sees with {{sadist}}ic relish, devouring or turning others into zombies. Upon finding Cheong-san, Gwi-nam doesn't care if all the other students are torn apart as long as he gets to torture and kill his nemesis.

* RomanticPlotTumor: One of the most hated elements of the series is that the approach of the romantic drama that arises from the love square between the four protagonists of the series and has made many feel that it is something that tends to considerably overshadow the theme of the ZombieApocalypse. On-Jo's initial characterization (aside from her BelligerentSexualTension with Cheong-san) is her unrequited crush on Su-hyeok and trying anything to impress him even during the zombie outbreak, focusing on Su-hyeok and Nam-ra's closeness at the moments more inappropriate. On the boys' side, one of the things that most characterizes Su-hyeok is his growing romance with Nam-ra and at the cost of this he ends up having minimal interactions with his other classmates after the two become an OfficialCouple. Tellingly, virtually the couples are separated for the most part during the Season 1 finale possibly in response to this.

* EvilIsSexy: Despite his abuse towards other students and (attempted) murder of innocent characters, Gwi-nam is considered by many fans to be pretty good-looking.

* SpiritualAdaptation: The show is basically ''Manga/HighschoolOfTheDead'' as a live-action series, sans the excessive {{fanservice}} of the anime. Both shows have at the core {{Second Year Protagonist}}s escaping a high school full of zombies, the handsome guy who has ShipTease with an upbeat tomboy and an AloofDarkHairedGirl, the fat friend being the PluckyComicRelief, a RichBitch with pink motifs, and green uniforms.

* TheScrappy: Despite being one of the main characters, Seo Hyo-Ryung is one of the characters that annoys or irritates viewers the most because she is a FlatCharacter with no purpose in the series. Not only is she one of the students who least helps or acts in fights, but she is constantly a DamselInDistress who has to be saved or serving as TheLoad when the rest of the survivors try to flee from zombies. Whenever there are times when her friends were in danger or in times of distress, instead of helping she stays quiet or gets scared and lets others take over. The fact that she survives to the end of the series unlike other much more interesting students like Gyeong-su, Ji-Min, Wu-jin, and Joon-yeong doesn't help either.

** Na-yeon infecting Gyeong-su just to be "right". Even after her remorse, amny fans refused to give her any sympathy when Gwo-nam killed her.

** A common criticism about the series is that it establishes a large number of characters to the main cast, but most end up unfocused and with no development on their personalities and backstories. While most of the cast members manage to have ADayInTheLimelight, sadly it still feels too little because it's right before the episodes of their deaths and there are even other surviving characters like [[ButtMonkey Dae-su]] and [[TheLoad Hyo-Ryung]] ending without even receiving focus and leaving them as {{Flat Character}}s.

* MoralEventHorizon: Gwi-nam is a gold mine for this. Bullying and even sexually harrasing several students to the point of them attempting suicide? Throwing four people to the zombies before he becomes a hybrid? Gleefully infecting multiple students with the virus? Torturing Cheong-san in front of his friends? He's done it all.

** Despite her horrible behavior earlier in the series, it's hard not to feel bad when Na-Yeong meets a bloody death at the hands of Gwi-nam. After Na-Yeong not only begins to feel remorse for causing Gyeong-Su's death but also remembers the sacrifice her teacher made to save her and tries to bring food to the other surviving students to apologize and fulfill her teacher's last wishes.

** Debatable. Western school systems are far from perfect when it comes to handling any kind of bullying, and victim-blaming is not uncommon. [[ValuesResonance Many victims of bullying can relate to how it's portrayed in the series]], from the ostracization of other students, to none of the adults helping in order to protect their own reputations. (Granted though, the spread of child pornography would be ''much'' more likely to be taken seriously by a court, even if it didn't actually help the victim much.)