First Window is not a game per se, but an interactive multimedia which focuses on the twelve heroines from the main game and by being released prior to the actual game, provided introductory into what was to be expected from the game, at least graphics, voice-acting, and heroines-wise. Second Window disc was included as a bonus disc with retail release of the game. With First Window, the player can check video that shows the audition for all twelve heroines, and separate set of 12 short videos containing introductory speech from each of the selected voice-actresses for the roles. Additionally, player can check detailed info about the heroines with an interactive gallery that requires user interaction to play through to the end, otherwise remaining idle with the same background music.

This supplementary fandisk also comes with a 12-months calendar, similar in style to the one released with the original game. The calendar starts from April 1997 to March 1998, featuring one heroine per month. Featured heroines in order are Kaho Morii (April), Honoka Sawatari (May), Asuka Hoshino (June), Emiru Nagakura (July), Rurika Yamamoto (August), Wakana Ayasaki (September), Akira Endou (October), Chie Matsuoka (November), Yuu Nanase (December), Taeko Adachi (January), Miyuki Hosaka (February), and Manami Sugihara (March).