My two complaints first:

- this anime series has an inherently flawed character design. Although the heroes are supposed to be young adults, their heads look like that of a child's. Their head shape is too round, their eyes too big. This becomes especially obvious when anyone's mother is next to them, and the mother basically could as well be their sister and it wouldn't looks out of place, either. I know that anime in general has an issue to properly display the difference of ages in the 13-30 yo range, often times there's barely a difference and height and clothing are the only way to tell. But KnY is especially bad in that regard.

- That upper-demon totally lacked any "oomph" until the end. All other shounen series I know did this better. Akatski in Naruto, Captains in Bleach, Admirals in One Piece, Freezer/Cell/Boo in Dragon Ball, Geneiryuudan and the upper Chimeras in HXH - they made me immediately feel their threat-level. This upper demon just had a too generic, lame design and there were no special effects to somehow mark him as more threatening than other demons.

THAT ASIDE: Fuck, I started crying during the "raven delivers the message to everyone"-montage. >_< That broke my heart. And then that fucking demon didn't even die. I had hoped that somehow Tanjiro's final attack would have opened the forest enough to let the sunlight reach that fucker.

Zenitsu didn't haven much appearance, but the one he did was fantastic. Both showing off to Nezuko AND awesomely saving people with his lightning move. However, it wasn't explained how he actually regained consciousness. The dream demon even mentioned at one point that Zenitsu hadn't woken up at all. Considering Zenitsu's technique relies on him falling asleep, it would have been interesting to see more closely how things went down here.

Overall, I enjoyed it, but it lacked movie quality. The animation was good, but so was the first season's. I'm glad this was made in a movie, though, because otherwise it would have taken up sooo many episodes, possibly an entire 2nd season. But wtf: How long is the manga supposed to run? Unless there's a mass-killing event where most upper demons die at once, the pacing will be super slow. After all this, the author wouldn't even let one of them die?! I guess at least it makes for a cool "re-union" when Tanjiru meets that demon again who's still having his sword now.

Very curious to see how our three heroes will grow stronger, because they're far below the level to fight with the upper demons.