Last Prom is a RPG Maker horror game released in 2014 by Jerimin 19.

Two best friends went to prom, only for one to be found dead the next day and the other gone. One year later, Violet Mizushima and Mika Kawaguchi are looking forward to their prom night, but the former is being targetted by a ghost girl in a white dress. After Mika tells Violet the story of the last prom's incident, they find themselves in a ghostly version of their school and seeking to escape from malevolent spirits. You can find the game here.

For the educational movie, you can find it here.

Examples:

• Accidental Murder: Sarah's death was caused after she tried to fatally stab Clara in a fit of jealousy only to get herself killed in the struggle.
• Asshole Victim: The kind of person Sarah is shown to have been in life prevents the audience from having too much sympathy for her, even without taking the subsequent murders attempts into account.
• Author Avatar: J19, being a surrogate for Jerimin 19 herself, appearing as a mysterious girl who gives cryptic talk to Violet.
• Big Bad: Sarah Motou is the vengeful ghost who wants to ruin prom.
• Brainless Beauty: Despite her beauty and kindness, Clara was oblivious to Sarah's unsavory nature and had below-average grades.
• Cassandra Truth: Violet initially doesn't believe Clara's seemingly outrageous claims about Sarah - not that you can blame her.
• Clueless Chick-Magnet: Despite changing so much, Clara remains a kind friend to Sarah, though she remains blissfully oblivious to how different their social lives are and is unaware of the more unpleasant aspects of Sarah's personality until it's too late.
• Cool Kid-and-Loser Friendship: Mika is a bit of a nerdy, quiet girl while Violet is outgoing and popular.
  • Clara and Sarah have been friends since early childhood. Unfortunately they drifted apart after Clara became popular and it only goes worse from there, with Sarah becoming dangerously obsessed with surpassing her and rejecting Clara's attempts to reconnect. And then the prom happened....
• Dead All Along: Clara, being one of the two friends from the last prom incident.
• Dark World: Violet and Mika find themselves trapped in a darkened, decayed version of the school.
• The Ending Changes Everything: The True Ending shows how Sarah was able to get a hold on Mika. After the last prom incident, the Motou family moved to France, with Mika's family moving into their house. Sarah continues to haunt and negatively influence Mika.
• Evil Is Petty: Sarah, to the point she tried to kill her best friend during prom night because she was jealous of her popularity. Even after death she still sees herself as a victim.
• Green-Eyed Monster: The true reason of Sarah's grudge against Clara.
• Freudian Excuse Is No Excuse: Sarah's tragic death might have made her somewhat sympathetic, if not for the fact that even when she was alive, she was a spiteful bitch who tried to kill her Only Friend out of petty jealousy and as a ghost, she tries to corrupt Mika into killing the innocent Violet because she wants to prove losers can't be friends with popular girls.
• History Repeats: Once again a Cool Kid-and-Loser Friendship goes wrong because the loser is dangerously envious of the cool one. And Sarah makes sure to feed on Mika's insecurities by manipulating her into killing Violet.
• I Just Want to Be You: In the Golden Ending, when the ghosts of Mr. Oshiro and Clara talk about Sarah, he points out how she rejected all of Clara's attempts to reconnect because she loved the idea of getting popular more than she loved her best friend.
• Indifferent Beauty: Violet is very beautiful and has attracted nearly every male classmate, she however remains apathetic towards all the attention, much to Mika's jealousy. It's implied Clara and Sarah had a similar dynamic.
• Informed Attractiveness: Everyone who sees Violet or Clara always makes a note on how cute and attractive they are. While the art is full of Generic Cuteness, they stand out as the only ones who are consistently given this treatment.
• Innocently Insensitive: When Clara meets Mika, she praises her for being friends with the most popular girl at school. Since Mika had shown envy at Violet's beauty earlier, this comment visibly hits her a lot more painfully than Clara had meant it.
• More than Mind Control: Although Mika's being affected by Sarah's manipulations, she's much more susceptible to it due to her insecurities.
• Multiple Endings:
  • Bad Ending - Goodbye, Best Friend: If Violet chooses to trust Sarah but didn't get all diary pages, the ghost girl kills her and traps her soul within the school. Mika wakes up in the living world, having forgotten all about Violet.
  • Bad Ending - Fake: If Violet chooses to trust Clara but didn't get all diary pages, Sarah is enraged and promises to get back at Violet. When Violet tries to leave the ghost world, she's confronted by an angry Mika, who claims Violet is a bad friend just like Clara was to Sarah. She then murders Violet as a gleeful Sarah watches.
  • Bad Ending - Blind: If Violet chooses to trust Sarah and got all diary pages, as she's about to leave the ghost world, she realizes that Mika was working for Sarah all along in order to test if Violet is a loyal friend. Violet chooses to sacrifice herself to free Mika, who is sent back to the living world. Sarah kills Violet, but not before admitting she was no victim, and tried to murder Clara out of jealousy for her popularity, only to accidentally kill herself.
  • True Ending - Unrevealed: If Violet chooses to trust Clara and got all diary pages, she finds a control room where Sarah and Mika had been watching Violet's misadventures at the spirit world. With Clara's help, Violet tells Mika the truth of how Sarah died and how she wasn't an innocent victim. Angry, Sarah sends Violet and Mika back to the real world. As the ghost of Clara, Mr. Oshiro and J19 talk about the incident, they find out that Sarah is still haunting Mika.
• Police Are Useless: After the prom incident, Clara is a prime suspect in Sarah's death because they never found her body. Turns out her corpse was in the school well all along.
• Prom Wrecker: The game happens during prom night.
• Sequel Hook: In the True Ending, Sarah remains a Karma Houdini and her ghost continues to haunt Mika.
• Skewed Priorities: After Sarah tries to kill Clara and gets fatally stabbed in the struggle, the latter tries to help with her friend's injuries. Sarah has a sudden image of people praising Clara as a heroine for trying to save her dying friend. The fact that people would think this gives her the strength to stand up and kill Clara. Even worse, she died of blood loss while disposing of Clara's corpse instead of trying to get help for her own injuries.