I watched both Battle Royale (original cut) and Battle Royale 2 (original cut).
I watched the first one after reading about how it was its 20th anniversary and in the article it gave more context for what was going on in Japan societally in the 90s when there was the big economic recession. It added a bit to watching the movie again, but I still think the movie pales greatly in comparison to the book. Granted, the movie was probably only ever going to pale greatly in comparison to the book because the book is ultra long, but it's still an okay movie.
I then watched the second one, and it's been so many years removed from when it came out that it's kind of shocking to go back to the time when it came out. It came out in 2003 as a response to the wave of terrorism in the early 00s, and watching it now is like opening a lid on the way things used to be. Still a really good movie in my opinion, though. It's been widely panned as crap, but I liked it. Next time I've got to watch the Revenge cut. It's been forever since I've seen that one. Finding it in HD is harder than finding unicorn poop, but I do have an old bootleg DVD. It's a slightly but importantly more complete experience.