There is a mysterious group of people who inflict cruel and fatal games on people for their own amusement. Tatsuya and Misa are out on a date in an amusement park when they wander into one of these horrific competitions on the tallest roller coaster on earth. The seats fall out of their 12-person roller coaster car, and they are told that the game will end when all but one person has fallen to their death. Will the passengers be able to find a way to escape the competition? Will there be any retribution against the orchestrators of this sick crime?

"Lured by the sweet fragrance of the flowers which blanket the earth, with fangs of steel and claws of iron, to the Garden of Eden which welcomed the ages, under the guise of a disaster from the heavens... seven dragons appeared."

Based on the game with the same name.

This is a cinderella-like story in which a shy and common girl gets a pair of glass slippers. The slippers enable her to transform into a cinderella. In this form she's loved by the guy she has a secret crush on.

7 Short Stories About Sex (spanning across 11 chapters):

1-3. 7 Daime no Tomari (The Seventh Generation, Tomari)
Tomari is a cursed woman who must do specific sexual things with her partner or the curse will kill her. Her partner, randomly chosen by the curse, is a guy called Naoki. He's pretty much willing to do whatever she needs, but Tomari will have to get past his incestuous sister Kyoko first.

4-6. Hajimete to,
A teenage couple, Seriko and her boyfriend Ogihiko, find themselves caught in a plot from her crazy yakuza family to make them lose their virginity together.

7. Sandy Go Home
Yoko returns from studying abroad in America with her sex-crazed roommate Sandy, and they both proceed to fight over who gets to have sex with her brother.

8. Mete Yunde
After their parents died in a traffic accident, Morote's two older sisters became insane. Is he safe in the house with them any longer?

9. Pastel Ivory
School kids have a sexual encounter in a bathroom.

10. Ninjia Shoujo Makari Tooru
When a ninja invades a girl's bedroom, he finds himself completely outmatched by her skills, both ninja and erotic.

11. 80D
A couple has a sexual exploit in a library after hours.

From Shoujo Crusade:

One day, while in search for more food, our heroine stumbles upon a jar of what looked like umeboshi; little did she know that it would bring her more than just a full stomach. The mysterious snack somehow makes her shrink and she can only grow back when she eats something (which is a bit of a chore if you're THAT tiny). And if that's not troublesome enough, she's also dealing with her crush who seems to like her best friend!?

From Yes_Rhade:

Chuunri's in a predictament - he's newest boyfriend doesn't seem to be interested in being intimate, so he goes to his previous boyfriend for advice. Of course, a little jealousy never hurts to get some action going.

Satou Atsushi isn't neglected by his family so much as ignored completely. Left to fend for himself, Atsushi fails to learn human speech and instead learns "cat language" and "Dog language" from the family pets. When he's eventually socialized with other children, his speech is stunted and his social graces leave something to be desired. But on his first day of nursery school, he meets a gloomy blonde with the same last name who seems to be a safe enough choice in a first friend. After developing a rather sizeable fixation with Satou Manato, he finds out that there his first friend is seriously ill and has a twin; Shuuto.

Years later, two other friends begin school and find that there are two Satous in their class too. Two Satous who, at first glance, could easily be mistaken for twins, but there's a bit more to things than it first appears...

After a tragic accident at a large facility 6000 meters below water killed its workers, the facility was abandoned for three years. After the Japanese company owning it is taken over by a Chinese company, the facility will be opened again. Kadokura Kengo and his colleague Danzaki are sent along with the team reopening the underwater facility. However, right away, an 'accident' grievously injures Danzaki. Kengo is left alone with colleagues he doesn't trust in an eerie underwater environment that may have more to it than meets the eye...

Two girls just started dating at the New Year Eve. They want to make up their lost kissing time and decide to kiss for 6 hours and 5 minutes.

From An Endless Story:

If you ride a train you can see there are a lot of different people. I wonder where they came from and where they are going. I've been able to hear many conversations and I wonder what kind of relationship these people have. I want to talk to them and ask, but I would be weird if I did so I just enjoy imagining it by myself.

A graveyard in contemporary Israel has an unlikely visitor. The elderly gentleman from Japan, a former news correspondent, lays a bouquet of flowers at the tomb of one Adolf Kamil. For he remembers the tale of three Adolfs: Kamil, a Jew who grew up in Kobe, Japan, the son of a baker; Kaufmann, only child of a German consul stationed at that port city and his Japanese wife; and the Fuhrer with whom the Far Eastern nation made common cause.

Won the 10th Kodansha Manga Award for general manga in 1986 (shared with What's Michael?).

Sold into a king's harem, the slave Adele learns that she has become the property of a man rumored to be so cruel that he executes his female slaves after they spend a single night with him. Determined to learn the truth, the brave young woman volunteers to be the next one taken to his bed. Is the man truly a murderer, or is there another reason that so many young women have disappeared from the palace?

Haizuka just wants to live a normal life, a peaceful life far away from all the trouble he's faced. But as soon as he starts highschool, an encounter with a girl and a strange creature destroys any hope of a peaceful life.

From Aerandria Scans:

The small country of Adarshan recently conquered a territory of the Castoria Empire. To create an alliance between the two countries and secure new border alignments, the victorious Adarshan general, Alexid Deke Adars (the king's younger stepbrother), was forced into a political marriage with Castoria's sixth imperial princess Justinia. But she's only 10 years old!

Reika Ryuzaki, daughter of the late diamond collector Yoshio Ryuzaki, is a jewel specialist who fights with knuckles branded as "Krishna" in cases involving bad guys who rob or misuse jewels for their own gains. She has an advantage in fighting as she can summon spirits from certain jewels to aid Reika in making her a better combatant in the field.

From Basement Leisure:

Kazuma is a shy high-schooler who happens to be gay, and in love with a popular and handsome guy,Ayase! A while later, Ayase befriends Kazuma, having found out that Kazuma is gay, and admits that he too is gay, and has the same feelings for Kazuma! Yet all Ayase does is have sex with Kazuma, causing Kazuma to feel insecure, will this relationship work out, or will Kazuma's and Ayase's heart fall apart?

"I am, in fact, one of the dead."

So says Acony, a rather mischievous girl, upon her first meeting with protagonist Motomi. Newly moved into an ancient apartment, how will Motomi handle Acony and all the bizarre residents?

From Ivyscan:

The Lord of Sanwa's son Lamkha saves Kanan, who collapsed on the road, and brings her home. In Sanwa, where the Messengers of Heaven or Flying Serpents roam the skies, a legend has been passed down the generations. According to the legend, a Holy Dragon fell from the heavens following a battle against a Black Dragon and was buried in Sanwa. What is the truth behind the legend?

A Violinist That has talent and seemingly more connections than he lets on is used to babysit a powerful SS rank illusionist girl she seems to have known him since she was young but he most likely don't remember her. ~ Yeavon

Izumi starts high school on a low note. For some unknown reason, rumors refer to him as the notorious Izumi, a thug who loves to fight. The truth is dramatically different. Izumi is the housekeeper for his widowed father, and spends his after-school free time doing the shopping, cooking and cleaning. He doesn't have the time or energy for friends, so his bad reputation actually is useful.

But what is the problem with Segawa and Sawatari? Why are the school idols always being so friendly with him? Don't they know about his reputation? What sort of friendship do they have in mind anyway? Why does Izumi start to feel like a ham-bone caught between two hound dogs?