There are three playable characters, one from each of the schools: Nagisa, Hikari, and Kizuna. They have no family names in the game, as when the series of short stories were first published. While Ai Shimizu maintained her role for Kizuna in the game, Miyuki Sawashiro performed the voice for Tamao Suzumi. The game features a "boy mode" and a "girl mode". Choosing the male version means that the story is told via emails from the player's younger sister; choosing the female version means that the story is told in the player's own diary. The player is given the chance to pair their chosen character with one of the other nine available girls, not including the other possible playable characters. There are twenty-seven different combinations depending on which girl the player chooses at the start of the game.
