Old.....the fucking Earth is old, it still is a pretty damn nice place to be. A lot of classic movies are much better than what is now being produced, try them.
Battle Royale is a classic but the act of Japanese students killing each other is pretty common I think. Success in movies breeds copycat (some actually that surpass the original though most fail miserably). It is always hard to say what spqawned what unless someone owns upped to it. The Japanese anime movie "Ghost in the Shell" was the inspiration for "Matrix". "Kill Bill Vol 1" (one of my all time favorite movies) was inspired by the Japanese movie "Lady Snowblood", which was made in 1973. "Hunger Games" was actually based on a series of novels yet there are many simularities to "Battle Royale"....coincedental or not.