One of the best mysteries anime i've watched, i loved how Tenma still stand for his own idealism till the end, also the fact that Nina didn't become another monster while she's capable to replaces Johan. almost every characters has depth, but i don't like the way they got introduced, it feels too rushed and somehow we were forced to understand that "this character is connected to another character."
The last thing i hate about is the cliffhanger, idk but probably that is the author's way to make us dying of curiousity.
If you enjoy Banana Fish, then you'll enjoy this one too.