I read Lady Hyegyeong (Sa-do's wife)'s memoir about this incident, and the story is so much more harrowing than what is portrayed in the film but it's still so good!
I watched this after reading Akutagawa Ryunosuke's original In A Grove story, and the movie really outdoes itself, with the acting, cinematography, and the integration of two Akutagawa short stories. It's absolutely incredible, Kurosawa is one of the greatest filmmakers.
Was disappointed they changed Levi out for Shikishima... they're essentially the same person, couldn't you have kept one of the most popular characters from the show in there!?
CGI is questionable but definitely did the job of creeping me out. I could see where they tried to recreate scenes from the anime, but of course the original is always better. For those not familiar with the anime, I recommend watching it eventually. The story is much clearer with more deep and diversified characters. As a stand alone movie, however, I think it does a pretty interesting job of story-telling, with some flat characters but I can overlook that for the amount of time it took to CGI every freaking Titan.