Dear god, never watch Battle Royale 2. That is the biggest piece of crap movie that came out of Japan I have ever seen. Imagine a made-for-TV movie, but drag it down even further. That's the shallow movie you don't want to see.

The first one is an amazing must see. It's really not as shallow as you might think. There's a lot of depth to the reason why the adults are putting high school kids on this island. I've heard the manga by the same name is better, but if you're short on time, Battle Royale is a great movie.