I think that this is a good anime to watch, but it isn’t really worth rewatching.
So I watched this anime as a 13 year old, and to be honest, I think it’s a fine anime for middle school age and above to watch, as long as the audience is mature and can handle explicit content.
To be honest, I didn’t find this too violent. In terms of violence, animes like Attack on Titan are way more gory and gruesome. The violence just seemed kind of empty. Most of the characters didn’t have much emotional depth (With the exception of Akira and Miki) and it was just kind of hard to connect to the characters and their perspectives. I also found the sex scenes a bit unnecessary. It’s obvious that it wasn’t fanservice, but it also just didn’t add much to the plot line.
Altogether, I would say that this is a good anime with a good concept, the darkness of humans while faced with fear and such, but it wasn’t emotionally deep or anything. It was just a lot of senseless violence and sex until the last few episodes, when the characters started explaining and conveying their feelings and emotions. By the end of the series, I was pretty invested in it, but until the end I wasn’t that interested in the anime.
I would say that this is a good anime that I would recommend to people, but I wouldn’t rewatch it. It’s a good anime though, and if you start watching it and have second thoughts, I promise, the animation does start getting a bit better after the first episode, and after a while it isn’t just senseless violence and sex. It isn’t great at first, but it’s worth finishing the anime.