Large PonPon

 Large PonPon (ら～じPonPon Raji Ponpon) is the first game that 0verflow created, and it established the setting that most of the later games, including the Days series, grew out of. It was released in 1999, preceding PureMail that came out the following year.

Although it was the first game produced by IRL timeline, in the universe's timeline it is not the first game. Two characters appear as old ladies in this game who appear as young ladies in later games while one cameo as a mother, making them prequels to this.

Story
Ayumu Inou's girlfriend, Rurika Washino, drops a bombshell on him: she'll be transferring to Paris for her new job. They then have sex one last time for good memories. Four months later, Rurika returns, with another bombshell: she's pregnant. After a heated argument, Rurika takes off.

Ayumu later discovers that Rurika is in a maternity ward, where he also crosses paths with childhood friend Yukari Nagawa, and begins an affair with Touri Sawagoe, another maternity patient. Will Ayumu be able to reconcile with Rurika?

Gameplay
The player plays as Ayumu Inou, the salaryman protagonist. Gameplay mainly consists of choosing location within the town that Ayumu lives in for an event to trigger. During the events, Ayumu will interact will various heroines such as Nurse Yukari or side characters such as Touri's husband Tomomasa. Interactive choices are present ocassionally which will decide the heroines' affection point toward Ayumu which can be seen in the menu.

Depending on the choices made and activated until the last day events Ayumu will reconcile with Rurika, move on with one or more heroine(s), reconcile with Rurika but having an affair with one or more heroine(s) or end up alone.

Main characters

 * Ayumu Inou, the protagonist


 * Rurika Washino, Ayumu's girlfriend


 * Misaki Washino, Rurika's younger sister.


 * Yukari Nagawa, a nurse and Ayumu's childhood friend. Rurika sees her as a rival.


 * Touri Sawagoe, a neighboring patient to Rurika


 * Kaori Itazaki, a teenage girl who is repeatedly seen at the hospital


 * Tamie Kirishima, Rurika's boss


 * Satsuki Shigehara, a mysterious girl who appears frequently at the hospital.

Secondary characters

 * Tomomasa Sawagoe, Touri's husband.


 * Arisu Takatsukasa, the head nurse and Yukari's boss


 * Mother-in-law, mother of Tomomasa


 * Obstetrician, an obstetrician who tends to Rurika and Touri.


 * Sempai, Kaori's (ex-)boyfriend