The entire prologue where you get to see the first two murders of the Return of the New Generation Madness. Ootani's death in particular since everything about his situation and inner monologue are all shown and narrated in detail.
The Sumo Stickers scattered all around Shibuya and the effect they have on Gigalomaniacs.
Yui's murder. She's cut up into individual pieces by a mind controlled Itou and stuffed into present boxes that are laid out in her body shape.
