So it ends, every good thing must come to an end, it was a enjoyable ride.
What happened to the Demon girl that was playing the mandolin? the one that created warps and stuff, the last time we saw her she was being manipulated by Yushiro, we didn't saw her die or at least I can't remember if she died and if she did then she was killed off-screen.
I don't think we needed a longer flashback of Muzan, we already had his flashback and plenty of other flashbacks in the last arc so giving more flashbacks would just be overdoing it, it's better to end this gracefully and not mess it up by extending the story with more arcs or more flashbacks, this is the problem with a lot of shounen mangas or animes out there, they just like to extend the shit out of it with plenty of crap.
Now I just wish that the anime's movie and 2nd season have Zenitsu screaming less because I found that guy extremely annoying, I like him in the manga but I absolutely hate that retard in the anime, he just ruined it for me.