On-line! Clear Fukano!? Akuma no Game! (Kadokawa Tsubasa Bunko)

[Machine Translation] Mai, a high school student, suddenly received a game called "Nightmare," a game in which she must play a game every day or she will lose one of her bodily functions. Once Mai gets her hands on the game, she is never allowed to stop playing it, and now it is all the rage in Japan! Mai, who is not very good at games, is now engaged in psychological battles with a slut and special skill battles with a reaper every day. The "Nightmare Strategy Club" is about to get underway with the shy Asagiri and the good-looking but difficult-to-please Sugiura, aiming to clear the game completely. From upper elementary school.

毎日ゲームをしないと、体の機能がひとつずつ失われる-高校生の舞のもとに、突然届いたのはそんなブキミなゲーム「ナイトメア」。一度手にしたら、やめることは絶対許されないこのゲームが、今日本中で大流行!?ゲームが苦手な舞も、口さけ女との心理戦や死神との特技戦とバトルの毎日。完全クリアをめざし、照れ屋の朝霧さん、イケメンだけど性格に難ありの杉浦さんらと「ナイトメア攻略部」が、いざ始動。小学上級から。