Woah that's weird. I just watched this film a few days ago, now I see this. Heh.
This is a pretty awesome stylistic piece! I see that you were trying to loosely base your art style around Ghibli's trademark look, especially with the character's mouths. And good god the backgrounds..! Good shit, man.
I do feel like the perspective is a little bleh with the way the foreground awkwardly interacts with the background, but it works.
Castle of Cagliostro is a film that really doesn't matter if you haven't seen the other Lupin III movies or show, since it's really it's own compact story that Ghibli fucked around with. Technically, this ain't even a Ghibli movie, but whatever.