The DVD set of Chikyuu Bouei Kazoku includes an alternative episode 11 (or 11.5), which features the opening of the world's first experience simulation game park, "Amber Crystal," in Chiba Prefecture. On the day of its launch, only couples are allowed to enter with a special ticket. Seiko and cameraman Hayakawa, along with Mamoru and Junko-sensei, meet up at the park. While playing the game, Mamoru takes on the role of a knight figure to earn experience points (XP) and steadily power up. Meanwhile, Seiko realizes that this game is actually an invasion by a space monster and sets out to confront its final boss.