His Act 1 bad ending is one, even if he had not drunkenly fallen to his death. He walks around the festival, lonely as he notes that none of the girls he met in his first days are available, and never emerges from his state of depression and bitterness.
For that matter, try to imagine the aftermath. Kenji is crazy, but I sincerely doubt he's going to take Hisao's death all that well, especially considering it's more or less his fault. And that's assuming he doesn't get held responsible.
Not to mention the reactions from the girls. Especially Emi and Hanako, who have experience with losing a loved one. OK, They weren't that close to Hisao yet, but Emi and Hisao have been running together while Nurse told her to keep an eye on him, while Hanako is scared shitless of making a new friend but tries to anyway. Then suddenly Hisao falls of the roof and dies. That's so not going to help them deal with their traumas.
The discussion after the exams, where she explains why she can't rely on you.
She leaves her mouth close to my ear, as she confesses this one thing to me.
Emi: Because, Hisao. I've already had everything I knew ripped away from me once. I don't know what I'd do if it happened again. ... So I can't rely on you. Or the Nurse. Or anyone else. Just me.
The scene with Emi opening up to Hisao, a week after she threw him out of her house for bringing up a touchy issue.
The conversation in the graveyard arguably counts as well. "Eight years ago today, I lost my legs. And I lost my father as well."
Hanako's bad end as well. It's already shocking enough to see her suddenly lash out at you, but what really drives it home is the fact that it's very easy to think the choices that lead to it are the right ones. Most of what you've done to try and help has actually been hurting her, and her rant against your insistence on protecting her is entirely justified. Again, this one calls What the Hell, Player? while forcing the reader to seriously reevaluate why they've become so emotionally attached to her in the first place.
Hanako: "Get out of my room, get out of my room, get out of my room…!! (...) I know I need help! I know I'm broken! I don't need you to tell me that! It's written on your face, it's written on Lilly's face, it's written on everyone's faces!”
Her Neutral ending isn't much better. She and Hisao do spend a much quieter evening in her room, having dinner and playing chess while making small talk... but there's a lingering sadness in the whole scene. Specially as it's implied that, while remaining friends, Hisao will keep to put his needs aside for hers, which will eventually turn their deal into a self-destructive one. Who's to say that Hanako won't eventually snap at him...?
Speaking of Hanako, the reveal of how she came to be scarred, and why she's got (some of) the psychological issues she has.
Hanako:The fire happened when I was eight years old. It was night, and I was sleeping when it started. I... curled up into a ball... when the fire swept over me. My mother... tried to shield me. Th-that's the only reason... I lived.
Hanako's panic attack is quite upsetting and rather uncomfortable to watch, especially considering that everyone involved tries to make things better after the inital faux-pas, but it simply doesn't work. The next time you see her, she's curled up on her bed, alone and weeping.
Hanako is basically a walking tearjerker. She's horribly scarred from a fire that killed her parents, one of which she presumably watched die before her very eyes, all her friends she had before the accident became her bullies and she was consistently bullied and excluded throughout elementary and middle school. At the orphanage in which she lived she had to see most other kids get adopted eventually, but was never adopted herself. Good god is that depressing.
Hanako's Good Ending will bring you to tears. She shows you her scars and tells you her mother sacrificed herself to save her. Then you both have sex. The next day, it's very awkward between the two of you and Hisao feels like he and Hanako are farther apart than ever. They both skip class and meet up outside so they can be honest with each other and themselves; Hanako didn't want to be just someone who needs Hisao or Lilly's help and she said that she wanted to have sex with him because then maybe he'd think of her as more than just a victim. Hisao thinks that he took advantage of Hanako and Hanako collapses to the ground and bursts into tears thinking that she ruined any chance of being with Hisao. Hisao holds her, cries, and confesses his love to her. Hanako is so happy to hear him say it that she cries even harder. They both regain their composure and take a walk into the city. Hanako gives Hisao her first gift, a kiss. All those feels...
Both of Lilly's endings evoke this to some degree, what with Lilly leaving for Scotland, never to return in both. The twist is that in the good ending Hisao refuses to accept her leaving, and decides to do a Race for Your Love and try to catch her at the airport before she leaves, only to get a heart attack just a few feet away from her, which makes it really resemble a bad ending until you hear Lilly's music box in the hospital. The music playing through most of the ending, Friendship doesn't make matters any better, either... What seals the deal is hearing the music box play while in the hospital bed. One of the best Chekhov's Gun in the game.
Rin's first H-Scene. It doesn't help that you find her alone on the floor, sulking and a complete mess. The dark background and music only makes things worse. It feels like you are destroying her in some way while you two have sex in her depressed, almost insane state. The possible bad end you can get after that is utterly soul wrenching just to top it all off.
Rin:Hisao? What's the word for when it feels inside your heart that everything in the world is all right?
Shizune's bad end you get for accepting Misha's advances. Oh, Christ. While most of the text remains the same as the Good End which has the theme of accepting graduation, having it change to have the underlying subtext that you went behind Shizune's back with her best friend makes every scene so uncomfortable. And it all ends with Shizune alone, heartbroken, without a friend in the world, staring vacantly on a stoop as you leave, leaving her completely and utterly crushed.What the Hell, Player??! And as one final note, the stuffed cat toy you won her in Act 1 is hanging out of her bag.
And the worst part? Shizune thinks that the reason Hisao and Misha have been acting so distant is her fault, when you were the one who went behind her back!
Perhaps the worst part about all this is that of the five girls and Misha, Shizune is the only one who actively desires to make friends note Hanako obviously has her issues with other people, as does Rin, but even the relatively popular Emi and Lilly don't let many people close for their own reasons, and sought to make people like her by doing things that she would make them happy. Unfortunately, in her alienating others through her desperate pursuit of her goal, she ends up coming off like a Tragic Hero.
Misha also implies that she was bullied for being gay, stating that originally she didn't want to go but the school sounded interesting, and that even if she was utterly hated by the other students, "at least they would leave her alone". It's awful to think that someone as cheerful as Misha would rather be hated by everyone then tormented because of her sexuality.
In the leaked beta script, Misha confirmed that she had been bullied. On top of this, she recalled an old conversation where Shizune told her that she didn't like Yamaku because it was where parents sent away children they were ashamed of, suggesting that not only did Misha think her parents let her go for this reason ("I'm one of those children nobody wants."), but that Shizune thought the same of Jigoro. While it's unclear just how much of this was preserved in the finalized backstories, it's heartwrenching to know that these were once very plausible concerns for the characters.
Misha's depression and eventual death in the leaked beta of the game.
Saki exists only in the 2011 April's Fool Joke by the developers, yet she got quite some attention, also because of her characterization which basically makes her a living Tear Jerker. While Hisao has to deal with a condition that puts his life constantly on the line, he'll be fine as long as he keeps up with his medication and gets some exercise. Saki's disease leaves no such hope: she may have from a few years to a couple decades left, but death will certainly come for her, and not before the disease will have gradually reduced her to a shell, finally taking away even her ability to breathe. She doesn't allow this to take the best of her, but even the happiest story with her could not be detached from a sense of constant sadness for the Foregone Conclusion that is her future. Katawa Shoujo might deal with some depressing stuff, but a story with Saki would likely blow all of the others out of the water in terms of making the reader cry.
The fact that Ritsu is a cameo character and her disability is, of all things, Carpal Tunnel Syndrome.