Let me start by saying that, yes, I read the Hunger Games prior to this. Initially I was shocked at how much the two stories resemble each other (yes, I am aware The Hunger Games were written after Battle Royale), but with the story advancing they move further away from each other. 
 The characters in this book are quite interesting, but I sometimes felt they were a little one sided. While I read a lot of mangas and watch anime I recognised some of the characters that are used often in japanese literature (if you don't want any spoliers regarding any character, although they are minor, you should skip this paragraph): There is the hero that is loved and adored and envied by many, he has almost no flaws, but often doesn't even recognise himself as the great guy he is. Then there is his sidekick that brings out the best in the hero and of course the female sidekick that's madly in love with him and he's completely oblivious to it. 
 Then there's the super powerful psycho, his dumb friends, his one not so dumb friend, the other psycho (in this story female) that has a horrible past, the nerds, the girls that are helpless and scared and always in a group. Well, you get my point. 
 While the characters may have seemed a little shallow it was still nice to see the story advance from different points of view from different school children. The story was quite interesting and didn't end in a blazing ending where everyone gets saved as american literature tends to do it, but of course you already knew that since the whole point of this story is killing each other. 
 The very graphic descriptions of the different deaths left me gagging from time to time - which isn't a bad thing - and made the destiny of these poor individuals all the more horrifying. 
 I do have to admit that the story had some nice twists that left me surprised or anxious, but other times it steered in directions that were all too obvious. 
 I can't say much about the writing style as I have no idea how Koushun Takami wrote it in japanese, but I have to say that the english translation was quite bad. It made sense for the characters to speak an urban english, since they're fifteen year olds from the city, but it seemed like the translator (or author) itself got lost in it sometimes and it was rather cringeworthy. But maybe that is just spoiled old me that prefers a well put language. 
 Another thing that bugged me a little was how much was going on in this class of forty people. There were murderers, prostitutes, criminals, gays, queers, rape victims et cetera. There was an awful lot going on with these people, regarding the fact it was a class of fourty fifteen year olds, but maybe it just seemed bizarre to me because I don't live in a country dictated by the government, leaving me with few legal things to do. 
 All in all I really enjoyed the book and the overall idea of these children in a death-match, although it wasn't the best performance. It was interesting to read and often left me anticipating the next thing to happen. 
 Ps.: And as always, sorry for any mistakes or weird sentences, english is not my mother tongue, I'm still learning. Thanks for reading.