Some nice, smooth, consistent quality. Better Call Saul was in my opinion pretty consistent. Single season anime is almost always consistent, like My Dress-Up Darling or Terror in Resonance.
Not dragging on longer than the series needs to seems to be a key point.
Yep, the entire series was pretty unhopeful for the fate of humanity, if it ended more like The Thing it would have been more keeping in tone, but idk maybe 80s manga had to have hopeful endings