YMMV / The Decagon House Murders

• Funny Moments: The manga adaptation features some Yonkoma at the end of each volume, showing the members of the Mystery Club in various amusing situations before the events of the story. Of note:
  • Poe shares some pictures of himself and Orczy from when they were children, and the fact that he looks older than his age is exaggerated for humor, with him standing as tall as an adult man next to the regular-size Orczy when they are both in grade school. He jovially tells Van that people sometimes thought he was kidnapping Orczy when he walked her to school, to which Van questions how he can laugh about that.
  • In their first year of university, Orczy and Chiori attempt to join the Mystery Club, only to initially be yelled at and frightened away by Carr. Then Ellery shoves Carr out of the way, and he and Morisu greet Chiori... only for her to be physically driven back by their pretty boy aura (subtitled "hottie wind").
    Chiori: Is this actually a talent agency? Where are all the nerds!?
• Hard-to-Adapt Work: In Japan, The Decagon House Murders is synonymous with this trope for spoiler-y reasons. The culprit is someone who was seen on both the mainland and the island, and the fact that these two characters are the same person is meant to be a shock to the reader, but isn't to any of the characters. Naturally, letting the audience actually see the killer's face or hear a voice at any point would immediately give it away. The book went unadapted for 32 years before a manga adaptation was published where the culprit's resemblance would stand out far less.
• Hollywood Homely: In both the novel and manga, Orczy has very low self-esteem related to her appearance, especially in comparison to the traditionally beautiful Agatha. In the manga at least, she is in fact very cute, and the male members of the Mystery Club express interest in her; she just dresses unflatteringly.
• Unintentionally Unsympathetic: The culprit, Van/Kyoichi Morisu, is intended in the novel as a Sympathetic Murderer trying to get revenge on his clubmates for their role in the death of his girlfriend, and chooses to turn himself in at the end. However, it's very hard to see him as that, given he kills all his friends over something which was very clearly a horrible accident, and even kills people like Orczy who had nothing to directly do with Chiori's death at all, purely because they were there at the party and did nothing. The manga amends this somewhat by changing the nature of Chiori's death to circumstances where he had legitimate reasons to blame the others for what happened, and he displays immense guilt when he learns that her death was a genuine accident.

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