The story follows high school student Tyler and his friends who get caught in a time loop, continuously repeating the same day seemingly without end.

Before long, they meet others caught in the same predicament who call themselves "loopers", and the two groups join forces to try to break out of the loop.

Loopers is the third of Key's "kinetic novels"—after Planetarian: The Reverie of a Little Planet (2004) and Harmonia (2016)—since its gameplay offers no choices or alternate endings.

The game's soundtrack was composed by Shinji Orito, Sōshi Hosoi, Donmaru, Hisashi Tenkyū, Shōyu and Sumi.

[1] Planning for the project began with video game director Kazuma Takada and producer Tōya Okano,[2] the latter of whom has been credited on the staff of Key's visual novels since providing scenario assistance with Air (2000).

During a production meeting, Okano suggested the idea of a geochache containing a human finger, adding an element of horror to the story.

As a result, Takada suggested to go with Mochizuki because of her distinct art style described as not only stylish, but that which also incorporates moe elements into it to make her character designs both cool and cute according to Ryukishi07.

At the time, Takada had been looking forward to what he termed a "large chemical reaction" that would occur from bringing together two creators who have very distinctive styles.

[10][11] Prototype released a Nintendo Switch port worldwide on June 2, 2022 with text support for Japanese, English and Chinese.

[14] The game's soundtrack was composed by Shinji Orito, Sōshi Hosoi, Donmaru, Hisashi Tenkyū, Shōyu and Sumi.