Background of the Work
The final boss battle is significantly harder than the preceding puzzles, which may frustrate those who aren't used to bullet hell games. If you enjoy puzzle-solving mixed with heavy metal aesthetics Touhou lore youmuinthe nightmaretaker akuma ni tsukareta 2021
The Possession: As the "Akuma ni Tsukareta" (Man Possessed by a Demon), the protagonist must navigate his social and professional life while being constantly pulled into a "Nightmare" dimension. He encounters "Youmuin"—a mysterious figure or guide within this realm—who seems to govern the rules of his torment or salvation. Youmu in The Nightmare Taker: Akuma ni Tsukareta
Note: If this refers to a real 2021 work not in my training data, please provide original source links for verification and documentation. Slow pacing and ambiguity may alienate casual viewers
The title "Youmuin: The Nightmaretaker ~Akuma ni Tsukareta" (often searched with the 2021 suffix) refers to a specialized adult-oriented simulation and visual novel developed by the studio Shiritsu Sakuranbo Nyuugakkou.