Forty hormonal Japanese teenagers on an island with three days to kill each other. The last one standing wins the "Battle Royale" that has been organised by the Japanese government to punish the unruly and ungrateful Japanese youth, and he or she gets to return home safely. If more than one survive, they will all be killed using the explodeable collars that are attached to them. These collars, which can't be removed, also track the heart rate and location of the students, and have microphones so that the adults managing the game can prevent any possible deviance.
Such is the premise of Kinji Fukasaku's Battle Royale; it's Lord of the Flies, but with unhealthy amounts of death and melodrama piled on. Each time one of the students gets blown up, stabbed, hanged, or shot with arrows and bullets, there's a friend or lover there to hold them and listen to their dying words. Strauss, Verdi, and Bach are there to make sure we understand how important this all is. Sometimes it's blatantly sentimental, and sometimes there's so much sentimentality that it starts to seem inspired.
There are other things here that make Battle Royale an interesting film. Much of the violence is striking, and the innocence in the interactions between students can be touching. In fact, because Fukasaku cares so much about his characters and the love and friendships they form, the whole movie feels innocent. Even the obsession with brutality has a moral justification; Fukusaku wanted to show what he felt when his friends kept disappearing in WWII and also wanted to satirize the cutthroat Japanese educational system and job market.
The other target in the movie is the adult world. Fukusaku shows the adults as incapable of comprehending what the adolescents are going through and incapable of surviving in the world they created. One of the boys keeps having flashbacks to his father's suicide--he's hanging half-naked at the end of a rope, and a piece of toilet paper at his feet has the word "courage" scrawled on it. The main villain of the movie, played by Takeshi Kitano, is the school-teacher who organizes and runs "BR." But he's hardly a villain in the traditional sense, since he spends most of his time looking forlorn and munching on biscuits; he's simply a man who's lost confidence in himself. Even if they'll mostly end up killing each other, the kids are the only ones with any hope of surviving.