- At the end of several chapters there are pages containing pictures of several characters, be they minor or main, showing how they were before the Zombie Apocalypse. For example the early mugger/rapist happily washing his car, Alice swinging between her parents arms, various high school students going through their days, and Asami being chided by her CO. The pictures are generally lighthearted but if you stop and think about them too much, they become tearjerkers. One especially heartbreaking picture is shown in the anime. Remember that gym teacher who jumped from a window? In his picture, he is lying in bed with a tiny baby laying on top of him.
- The end credits of the final episodes shows Matsushimanote run in front of a bulletin board featuring the photos of the all the characters. She pauses briefly to look around, then runs offscreen, into the night. This isn't so bad if you haven't read the manga. But if you have, you'll remember she was trying to find help for the survivors who were still trapped in the mall... except she doesn't make it.
- Midway through the third episode, as Takashi's group make their escape from the school with another group of survivors. When Takuzo (the one with the towel) gets mobbed by "them", his girlfriend, Naomi, becomes so distraught that she runs back to him - knowing she couldn't save him and that she would die along with him. Yet she didn't care, so long as she could be with him.
- Alice's father gets fatally stabbed by a group who'd hidden in their home, when he was only trying to find a safe place for his daughter to hide. Instead, he dies trying to assure her he'd be fine, knowing that his 7 year old would soon be on her own with a horde of "them" gathered right outside and heading straight for her.
- Asami giving one final salute before Hirano mercy kills her.
- Takashi being forced to Mercy Kill Hisashi. Made worse by the fact that he wasn't fast enough to stop his zombification.
- Meta example: the death of series creator Daisuke Satō from coronary artery disease.
Tear Jerker / Highschool of the Dead
As a rule to every Zombie Apocalypse adaptation: It must beget Tragedy.