This anime is truly a masterpiece. I can't begin to describe the number of emotions it touches, there are times when you will find tears trickling down your cheeks before you know it. The idea of going into the cryptic abyss, a journey from which you can never return, in itself holds scope for so many emotions and the series does a great job at bringing them out. And believe me, this is one of those series which can be enjoyed by anyone, even those who conform to very specific genres. The story was so intriguing that you just can't stop watching as the mystery of the abyss gradually unfolds piquing your curiosity along the way. The fan base for dark anime will not be discontented as the series does take a dark turn midway, dark enough to leave you on the edge.
There were controversies about child nudity and I personally think there is not 'much' wrong in it. There is strictly a requirement for such visuals in a series that deals with survival and I feel there's no need to further elaborate on this. But, some visuals were shown to create hilarious situations and I guess these were the reasons for the controversies. I don't think the visuals were obnoxious as they were not very detailed and are no reasons for criticizing the anime.
For the series has so many overflowing emotions, dark storyline and the tendency to make you laugh in the middle of serious situations, I highly recommend it.
