After the original Corpse Party came out for the PC-98 in 1996, the series would idle until a second installment called New Chapter was released for mobile phones in 2006. During this downtime, a Fan Prequel was developed to fill the void, drawing inspiration from two sisters mentioned in passing in the original game.
Kaori Hasegawa enjoys scaring her little sister Shiho with ghost stories, teasing her for being so frightened by such fables. However, after telling her one about a girl who met a gruesome end in a nearby school, the two suddenly find themselves stranded in a broken down, abandoned building with no apparent way out.
In 2012, a Fan Translation was released by Memories of Fear. In addition, the original team is working on an Updated Re-release titled Corpse Party-0, which will add four new characters to the cast. So far, only a demo has been released, which Memories of Fear has also translated.
This Fan Prequel contains examples of:
- Apocalyptic Log: These can be found scattered around the school, providing warnings and hints. Shiho also writes one before her death.
- Big Bad: As always, the evil Sachiko.
- Big Sister Instinct
- Book-Ends: Just before they get pulled into the haunted school, Kaori scares Shiho by telling her about a girl who supposedly stood up after falling from the third floor. In the C ending, two schoolgirls tell a similar story about Kaori's suicide, while in the B ending, Kaori starts telling the same story to two unsuspecting students.
- Colour Coded Characters: Some of the spirits the girls meet are blue while others are red and fiery. Shiho discovers the hard way what this means.
- Determinator: Shiho becomes one after starting her fatal walk through the green goo. Despite the pain, she manages to make it all the way across, find shelter, and hold on long enough to write a final warning for her beloved sister.
- Distressed Damsel: Peril seems to always find Shiho first.
- Driven to Suicide: Kaori in the C ending.
- Doppelgänger: The evil spirits masquerade as both girls at different points.
- Downer Ending: Ultimately, Kaori can't save Shiho. Even if she escapes, the guilt may drive her to suicide, or she may deliberately choose to drag others into the dark world by retelling the story. Even in the best ending, she states she isn't sure how long she'll be able to endure the guilt and anguish of failing to protect her sister before she breaks.
- Evil Laugh: The anatomical model goes 'kikikikikikikikikikiki' constantly. The evil spirit also laughs a lot.
- Expy: Like Yuka before her, Shiho is the main character's adoring little sister who came to pick them up from school, only to end up in constant peril and relying upon her sibling's protection.
- Final Boss: In the final nightmare, Kaori and Shino can confront and defeat the evil spirit, then escape together.
- Foregone Conclusion: Shiho is the author of one of the warning notes found in the original game. Zero basically reveals how she discovered the information she wrote down: the hard way.
- Half the Man He Used to Be: The anatomical model reappears during the final chase sequence without his legs, making him much slower. Still don't want to get caught, though.
- Hair Decorations: Shiho has a yellow ribbon which she adores.
- Heroic BSoD: Kaori suffers one upon discovering Shiho's body.
- Heroic Sacrifice: During the final escape, Shiho's spirit flings itself into the flames blocking her sister's path.
- History Repeats: Many of Zero's events echo what happens in the original Corpse Party game. Or what will happen, rather. On top of this, the notes with feminine handwriting sound oddly like a conversation between two sisters, who mention a yellow ribbon, and one note refers to the dead girl from 2-9 as Hasegawa.
- Hope Spot: In a sense, all of the final nightmare, as it looks an awful lot like a Golden Ending... up until the final image.
- Involuntary Group Split: Thanks to the anatomical model breaking the loose board while Kaori and Shiho are on opposite sides of it.
- Kill It with Fire: The evil spirits look like flames and will inflict damage to Kaori's HP upon slight touch in the escape sequence. It's also possible to die in the school's incinerator.
- Mirror Monster: One of the mirrors does not show a reflection. Breaking the wrong mirror leads to Shiho's death.
- Multiple Endings: Depending on one's actions, there are nine different Bad Ends Kaori and Shiho can meet along the way, a few of which have small variations. (One has seventeen different versions depending on which of the flames hits Kaori!) In addition, the main ending has three variations hinging on how much willpower Kaori has at the end.
- "The Reason You Suck" Speech: Upon confronting the evil spirit responsible for their being stranded, Kaori verbally tears into her.
- Sanity Meter: Both sisters have a Willpower meter. If this dips too low, it can lead to a bad ending.
- Sequence Breaking: It is possible to finish the game and get the best ending available even after Kaori made the wrong decision escorting Shiho into the bathroom instead of waiting outside. Normally, this event would lead to Bad Ending, but the game coding does not register this as one as long as Kaori and Shiho refrain from going to Wrecked Hallway while having Iron Lever. The iron lever would eventually be used to jam the Science Lab door, preventing this particular Bad Ending from happening afterwards. Doing this choice will skip the whole mysterious mirror puzzle, thus the gameplay will become easier. Few players are aware of this exploit.
- The Stinger: The main ending has three different versions depending on which variant you earned. The final scenario also has one establishing that no, Shiho's still dead after all...
The Updated Re-release also contains instances of:
- Adaptation Expansion: While Zero focused solely on the Hasegawa sisters, 0 adds four male classmates to the mix.
- Blue with Shock: Some of the 'scared' portraits show a flush of blue between their eyes.
- Blush Sticker: Masayuki gets these whenever he's laughing or excited.
- Foregone Conclusion: The names of the new guys come from Name Tags found in Blood Covered. This will not end well.
- Involuntary Group Split: Shortly after hearing how lucky they are to be together, Kaori and Hideki end up on one side of a collapsed floor, while Shiho and Masayuki are trapped on the other.
- Like Brother and Sister: Masayuki and Shiho are seen like this.
- Peek-a-Bangs: Hideki has these.
- Plot-Relevant Age-Up: In the original Zero, Shiho is fifteen years old. Here, she's seventeen, specifically to put her at the same age as three of the new characters, with two of them being her classmates.
- Pointless Band-Aid: Yuuya has a large bandage that completely covers one cheek.