Nightmare Fuel: Considering this is a Yandere audio franchise, this should be expected.
Sonoko's track is pretty disturbing. She stabs Ayase in the stomach with a shovel and turns her in fertilizer. Sometime before the audio, she apparently killed The Protagonist and is using his skull as a flowerpot. Chances are that he wasn't dead for long so she probably removed his eyes, brain, hair, muscle and skin.
Nana and Nono's track is creepy. First off, they're little girls and they're the youngest Yanderes in the series. Second, they treat dangerous and normal things like a game. So when they're fighting Yuriya, they're giggling and treating it like a game. They don't even treat killing her like it's a big deal. They just move onto the Protagonist and kill him in the bathroom.
What an Idiot: Seriously, did you think that saying "Why are you twin girls so ridiculous?" to an angry Alice who is grieving her sister's death and is threatening to kill you was the best idea?
What about telling your yandere little sister that her rival's cooking is better than hers? You didn't think she was going to be a little upset with that?
How about hiding on the rooftop of your apartment building when a transgender yandere is chasing after you with a sword? Wouldn't going to the police be a much better option?!
The Woobie / Woobie, Destroyer of Worlds: Elise. All she ever wanted was some friends and someone to love her, but Alice stole every possible friend and boyfriend she could've had (including her current one) because of her incestuous love for her. In Alice's Track, she kills herself because she can no longer stand it. In her own track, she finally snaps and kills Alice then goes to live happily ever after with her boyfriend.