- The Danza: In the film, Kitano is played by Takeshi Kitano.
- Dawson Casting: Most of the cast was around fifteen (Aki Maeda as Noriko) or in their late teens (18-year-old Tatsuya Fujiwara as Shuya), but there are still two glaring examples: Taro Yamamoto (Shogo) and Masanobu Ando (Kiriyama) were 26 and 25 respectively when the film was released. The sequel also has a couple of examples, but not many. Makoto Sakamoso, who played Osamu, was 25 when he played the part. Ironically, his character is one of the youngest-looking.
- Development Hell: An American remake of Battle Royale has been in this on and off since 2006, likely because nobody in a post-Columbine Hollywood could seriously contemplate making a film about high school students killing each other. The 2007 shooting at Virginia Tech especially hurt the project. While the popularity of the film adaptation of The Hunger Games has given people some hope that it will one day be made, the producers have ironically said the opposite: that they won't make an American Battle Royale, at least for another decade, specifically because there's already The Hunger Games. A TV series idea also didn't go anywhere.
- Died During Production: Kinji Fukasaku, who directed the first movie, only managed to shoot one scene of the sequel before passing away due to prostate cancer. His son Kenta, who wrote both films, finished it and dedicated to his memory.
- Fan Nickname: It's not unheard of for people to refer to the Chigusa/Niida scene as the "crotch-stabbing scene". Take a guess why.
- Image Source: This film provides the page image for Scary Flashlight Face.
- No Export for You: The two Battle Royale films did not receive an official release in the United States for years as Toei had insisted on a full theatrical run (with promotion) for at least the first film instead of a mere home video release. No American distributor would accept the deal until Anchor Bay Entertainment bought the license and made plans to release a 3D version of the first film in American theaters in 2011. While those plans didn't pan out, Anchor Bay managed to ultimately subvert the trope by releasing both Battle Royale films on DVD and Blu-ray in the spring of 2012 (chiefly in an effort to capitalize on the publicity surrounding the film version of The Hunger Games).
- Real-Life Relative: Noriko Nakagawa and Shiori Kitano are respectively portrayed by sisters Aki and Ai Maeda in the films.
- Streisand Effect: Due to the novel's content, members of the Japanese Parliament actually attempted to have the novel - and later, the film - banned, to no avail. In fact, the government's efforts ended up unintentionally raising public attention towards both the novel and the film turning them into the classics they're known for today.
- What Could Have Been:
- Kyo, the lead singer of Japanese rock band Dir en grey, was initially offered the role of Yoshitoki Kuninobu, but had to decline when the band's manager forced him to turn down the role due to him being a Dead Star Walking.
- Quentin Tarantino was offered a role in the second movie but couldn't do it because of scheduling. According to him, they wanted him to play the President of the United States.
Trivia / Battle Royale