Kowloon Youma Gakuen Ki (2004)

A hybrid dungeon crawler/dating sim in which the player splits their time between making friends at their new high school and exploring the mysterious ruins hidden beneath it.

Storyline

The player assumes the role of a young treasure hunter who has learned of the existence of an ancient, treasure-filled ruin underneath Kamiyoshi Academy in Shinjuku, Tokyo. Entering the school as a faux transfer student, his true goal is to explore these ruins and unearth the treasures (and OOPArts) they hold. This is not an uncomplicated task, however: the ruins reveal themselves to be an upside-down Ancient Egyptian pyramid, guarded by traps and age-old monsters of Japanese myth – and the school's student council, being more than it seems at first glance, is equally determined to get in the way. The story is told as in an anime: divided up into "episodes", each one starts and ends with the same opening and ending sequences, and has separate sub-stories contained to each episode.