Nightmare Diary: Chapter One is a video game that follows Kohaku Suzuki as she wakes up from a nightmare involving a car accident with her love interest, Ichigo Sasaki. In this immersive and intense game, players must navigate through a world filled with nightmarish creatures and solve puzzles in order to advance. The game features puzzle-based battles and a unique mechanic that involves collecting diary shards. As players collect these shards, they will uncover the mystery of Kohaku's dreams and discover the truth behind the car accident. Along the way, they will encounter challenging bosses and puzzles that will test their skills and strategic thinking.