the anime adapted roughly 37 chapters out of 55 and the manga is still ongoing, so, there's that.
That being said, Production I.G delivered a phenomenal adaptation of this story. The author cleverly adds mystery on top of the mystery, and just as cleverly confirms or invalidates theories that may have emerged from said mystery, with visual cues or straight up dialogue. As if he was reading the viewers mind.
I really enjoyed your reactions and the extended discussions at the end of each episode. Looking forward to (hopefully) season 2