Shinobi is an amazing movie with a great cast of characters, a good storyline, and quality production value. If you were to freeze the film at several points throughout, you could see how well framed and composed these shots are. I don't want to leave any spoilers, period. Just take my word for it.
If you're an anime buff, you'll find that this movie well executes the transition of elements and aesthetic normally found in Japanese animation. Each character is unique and memorable in their own way and you'll find yourself satisfied with the amount of time you see them on screen. This movie has fantasy elements woven into details based on actual existing ideas in history such as the Ninja tribes, but just forget for a moment that anything has to be plausible, realistic, or historically accurate here. This movie is what it is.
The beauty of this movie is, it ends. You don't see any cop outs leaving room open for a sequel. This film is a standalone masterpiece and I'm happy to have it in my Blu-ray collection. If you're interested, see about picking up the soundtrack because there's an amazing track by Ayumi Hamasaki (Japan's Madonna equivalent, or better) called Heaven which is worth listening to.