25c: Sono Hako wa Shōjo no Himei o Morasanai

25c: Sono Hako wa Shōjo no Himei o Morasanai is a Japanese erotic visual novel with dungeon-crawling segments.

The player takes on the role of Kana Mishima, a girl who has been looking after her younger brother Yuki since their parents died in an accident that also left Yuki brain damaged. Kana passes out while at the hospital with Yuki one day and wakes up to find that they have both been transported to a labyrinth consisting of strange, windowless, cube-shaped rooms, many of which contain traps of a sexual nature. Will Kana and Yuki be able to escape with their innocence intact, and how far will they go for their freedom?

In the dungeon crawling segments, the player controls Kana as she navigates the maze and hopes not to encounter any traps. Kana has a life meter which will result in a game over if it is depleted by coming into contact with too many traps.