Ao Oni (Japanese for "Blue Demon") is a Japanese indie horror game, created with RPG Maker XP. It follows the adventure of four teenagers who go into an abandoned mansion (which is supposedly haunted) in order to investigate...Provided inspiration for Heta Oni, an Axis Powers Hetalia-themed parody/reinterpretation. Other games inspired by it include Aka Oni, Siro Oni, Niji Oni, Hakkyou Oni, Gon Oni, and Ao Oni S.Keep in mind that different revisions of the game may have significant differences within the plot.The game can be downloaded for free here. It managed to get a two-novel adaptation around 2013 and a theatrical film version in 2014. Seriously.
Ao Oni provides examples of:
Agent Scully: Hiroshi to some degree. This is demonstrated most in the third version; even after being chased around by the oni, when he catches up with everyone else and gets asked what's happening, he suggests it's some sort of Halloween costume. The oni disproves that theory, prompting a later dream where Hiroshi imagines he was right after all.
Anyone Can Die: Depending on the version. Sometimes Hiroshi might get to save everyone; other times, not so much.
Art-Style Dissonance: The character portraits in early versions are drawn in markedly different styles. Takeshi's in particular stands out.
Awesome but Impractical: There are closets in a couple of rooms. You can escape the oni by hiding in one of them. If the oni is in the same room as you, going in one will land you an automatic game over (your hiding spot is no good when the oni sees you go in). Good luck trying to hide in one without the oni catching you!
Behind the Black: The oni seems to like hiding behind text boxes to enter a room unnoticed.
Bittersweet Ending: In version 5, Hiroshi leads his friends to safety, but another group enters the mansion...
In 1, only Hiroshi, Megumi, and Kazuya manage to escape.
In version 6, Hiroshi ultimately escapes, but couldn't save anyone, making for a Downer Ending.
Book Ends: Two examples in Version 5's ending: Takeshi has a nightmare about being found in the cabinet he first hid inside, and a new group of victims enter the house.
Cue the Rain: As you move deeper into the manor, you will eventually hear it raining outside.
Curiosity Killed the Cast: Depending on the version. Everyone or nobody in the group dies. Markedly in version 5 where no one dies... But a new group enters the building. Whereas everyone but Hiroshi dies in 6.
Difficulty By Region: In version 5, there is a Japan-specific cipher puzzle which many non-Japanese players find almost impossible, even with the usage of a guide. Often times, this is the spot where players gave up on the game altogether.
Driven to Suicide: Takeshi, in version 6. He is extremely sad and guilt-ridden after convincing everyone to go into the mansion, only for most of them to get eaten, killed, or worse.
The original version puts more detail into the Excuse Plot with a longer opening sequence. While the main character is still named Hiroshi, he's now a dark-haired underclassman who, along with the silver-haired Kazuya, gets forced to visit the mansion by a gang of four older students. Takuro leads this gang, and the other members include Mika's precursor Megumi, a brown-haired Takeshi counterpart, and a gray-haired boy who would eventually become Hiroshi in later versions. There are no character portraits.
The oni suffers heavily from Artificial Stupidity in the original game, having a harder time navigating around obstacles. By the same token, certain objects can be walked right through.
Easter Egg: In the later versions, these can be accessed by entering different codes for Hiroshi's name.
Fan Sequel: The fangame Ao Oni S is specifically set after version 5's ending. There's also Siro Oni, Hakkyo Oni, Heta Oni, and Crom Oni, each with, respectively, a Two Headed Oni, a Bleeding Screamer Oni, a sort of Alien-like Oni, and a Red Oni. Finally, there is the Axis Powers Hetalia parody called Heta Oni.
Fountain of Expies: The oni game, as well as the RPG Maker horror game became genres thanks to this game.
Four Is Death: In most versions, it's a group of four students who enter the manor.
A Friend in Need: Most strongly seen in the first version, where Hiroshi is constantly searching for his friend Kazuya, and Kazuya ultimately saves him in the end.
Gory Discretion Shot: Used in conjunction with Shadow Discretion Shot for one death: after seeing a shadow pass by a screen door, attempting to enter five times will let Hiroshi actually go in, while the 'camera' stays out in the hallway.
Grand Theft Me: What happens to all the friends in version 6 after they are killed by the Ao Oni.
Quite possibly part of the reason Takeshi kills himself in the middle part of the game, to prevent the Onis from doing this to him. It doesn't work.
The cutscene when you're trapped in the jail could count. But if you really want a Jump Scare, hide in a closet with the monster in the room. At the end of the game, you get one of these with a horrifying sound to boot.
Some puzzles take you to a different screen to solve them. During one such instance, you'll make 2 moves in the puzzle before it freezes... AND THE MONSTER IS SUDDENLY WALKING STRAIGHT AT THE SCREEN. And yes, he is right behind you when you return to the normal map. Needless to say, it's a tad unnerving.
Kaizo Trap: If you don't run from the mansion after escaping, the Oni will CHASE AFTER YOU OUTSIDE!
Leaning on the Fourth Wall: The monster will, at times, use the text boxes to its advantage. In version 6, not even the status screen is safe!
The South Park spoof Lampshades this when Takeshi screams at you for talking to him, because he knows the Ao Oni's been using the text boxes to pop up behind its victims.
Markiplier is doing a playthrough now as well. His playthrough is of version 6.
Let's Split Up, Gang: While splitting up in the first place is involuntary, when Hiroshi actually finds his friends, they rarely agree to sticking together.
Lovable Coward: Takeshi and Mika, but mostly Takeshi. He is found hiding in wardrobes twice throughout the whole game, and is the only person having doubts about going to the mansion in the first place.
The original version has Kazuya, who's simply terrified at being dragged to the mansion by Takuro and his bullies.
The chase music loops, and lasts around 10-15 seconds. It usually takes one full loop of the music to time-out the Oni and end a chase sequence. Therefore, the best strategy is to get to a room with several obstacles, and run around them until the music has to restart, then exit.
The fact that there is no chase music for Version 5's climactic chase should really clue you in that the chase never ends.
Non-Standard Game Over: In most versions, there is an early scene where you can walk past the clouded-glass door of the bathroom in time to see a large shadow pass by, with some very heavy breathing. Activating the door several times results in Hiroshi entering, but the camera staying outside. All we see is a smattering of blood on the glass before the game cuts out.
Nothing Is Scarier: In version 6, there's no music except for when a monster appears, which is a repeating Scare Chord. Also, at some points, the player has to hide in an empty wardrobe in the bedrooms; the screen goes black and the music is silenced. The only thing you can hear is the door opening when the monster enters to find you, then the door closing once it leaves. Even worse, in some cases, the monster will appear in the room just before you enter the wardrobe, thus causing a Game Over.
Scary Surprise Party: In early versions, this trope is cruelly subverted. The hero, Hiroshi, is suddenly attacked by the monster that has been chasing him and murdering all his friends, only for the Oni's head to pop off, revealing that it was a guy in a suit all along and that the whole ordeal was just a setup for a surprise birthday party. Pity that this turns out to be just a dream, and his friends really are dead.
Shout-Out: Right below, once you reach the part where Takeshi gets killedSouth Park Style, they copy off of Gantz and its Buddhist Mission alien speech.
Silliness Switch: If you enter "SOUTHPARK" as your name, the character sprites are drawn in South Park style and the dialogue is changed to incorporate catchphrases from the show. "Oh my god, they killed Mika! You bastard!"
Timed Mission: Most encounters with the monster involve running away while a hidden timer counts down. Entering TIMER as Hiroshi's name enables the player to see this clock.
Twisted Ankle: Takuro, in version 6. He hides in a closet, and gives you an important item; later on, you will come to collect him, but the monster ate the rope ladder you need to escape and chases you and Takuro. Then Takuro trips over and is eaten/killed/whatever you call it...
Vague Age: The main characters are consistently either middle-school students or high-school students, but what year they're in is never stated, putting them in the 13-15 and 15-18 age ranges. The only characters whose ages are definite are Hiroshi and Kazuya in Version 1; they're explicitly referred to as high-school freshmen (i.e. they must be 15 going on 16).
Was Once a Man: In version 6, your friends come back as monsters after they are killed off one by one. You can tell them apart from the original monster by their hairstyles.