My first impression of seeing Akakage (Red Shadow), was that the story was simply a satire of ninja movies. The Cinematography is quite good, and exemplifies many earlier examples of Japanese Cinema with their frequent use of nature interlude shots. The film seemed childish at first, in the manner in which the characters were portrayed.
But upon reviewing the film again, I noted that it was actually more child-like. There was a mature comedic sense of what a child loves in a film about ninjas and samurai sword fights. I could appreciate the nostalgic sense of the old samurai films that was ably caught. The villains seem comic in many ways, and yet there is more than 1 dimension to the group of them. The use of anachronism in the film was to me particularly funny. I won't provide any spoilers, because they are readily apparent when you encounter them in viewing the film.
Anyways, if you want a light movie for Saturday night viewing with the kids, or with friends gathered around a bowl of popcorn, and want a good offbeat romantic adventure film, this is certainly one to try.