This is an excellent anime movie. It is well animated, has a good intricate plot and very good music. I understand that some may think of it as a little long, but I think that it is a good length and the animation is good traditional anime.
THREE CHARACTERS:
The way they use Tenkai is masterly. For example the body double showing up at all these locations adds to the ominous tone of the movie. The design of Tenkai is good too, the way he looks as a monk and in the end scene the armour he is wearing.
The old man Andou is down to earth and a very likable character. When Jiro meets him it's a turning point in the movie.
Sanpei, the Satsuma Shinobi who infiltrated Tenkais clan saves Jiros life twice. He stays in the background most of the movie though, but he is really one of the heroes of the movie.
THE PLOT: The plot is good. It is traditional without being unoriginal. The historical time it is acted out in is interesting, The meiji restoration. The treasure is sought after by Tenkai to restore the shogunate while when Jiro finds it he uses it to help the anti-shogunate forces overthrow the shogunate.
The way Tenkai tricks Jiro is interesting and has sort of a "Hamlet" feel to it. There is also a sweet irony to the fact that if Tenkai had not gotten Jiro to become a shinobi I don't think that he had been able to kill him in the end(Maybe by firearm, but not hand to hand combat weapons).
The plot with all the death makes it mostly very dark, but there's some light moments when we see some of Jiros childhood memories. All in all it's a good, dark, intricate plot.
THE MUSIC: The opening theme for example is very good with the electric guitar and drums. They occasionally in that piece use what I believe to be taiko drums, but i'm not sure.
There is a lot of good music. Like the one played while they are traveling to the Iga shinobi. I believe the piece is called "Numatou" and has an incredible flute in it. The flute might be a pan flute, but more probably a shakuhachi.
The end theme "Kamui no komoriuta" is calm and delicate. The vocals are beautiful and so is the song in general.
THE ANIMATION:
The animation, while good, is not perfect and the blood that runs down the characters do sometimes appear to be orange. The transitions are interesting and I think some transitions are very nice. One example of a nice transition is when Jiro and the Iga shinobi are running, there is the sunset in the background and the music is playing. The transition is simple, but effective and has a nice feeling too it.
MY FINAL WORDS: I think that the plot, the animation, the music and the characters make this into one of the best anime movies I have ever seen.