Josh Tolentino: "Humanity Has Declined is an exceedingly smart show, at least compared to most of the fare that populates the typical anime season. It's a rare beast in any field of entertainment (cartoons in particular) that's willing to employ a sense of subtext and actually give the impression that it has something to say.
The message here is clear as its title, but its true success here is that the delivery comes off less like a polemic, and more like an off-hand admission, with a healthy helping of other things to think about for folks not into being depressed.
In that way, when Humanity Has Declined wants to talk about how humanity is in decline, it sounds less like a funeral dirge and more like whistling past a cemetery. Upbeat, but still a little morbid at the core, and that's not a bad thing at all."