Dororo is a great genre film. It's an adventure movie kind of akin to a live action 'Ninja Scroll'. In fact, by keeping a simple, straightforward plot (boy's father pledges a number of his unborn son's body parts to demons in exchange for power - years later the boy is a man, and back for revenge) it elevates itself head-and-shoulders above most films of it's kind, as well as the manga and anime equivalents, which tend toward overly complicated and downright convoluted, soap opera-ish plots.
On the other hand, it falls prey to many of the problems of those genres - perpetuating the trend. Problems that include science defying scenes (a little in a fantasy film is O.K., but it gets to a point where... well, suspension of disbelief becomes impossible... no one, let alone an infant is going to survive even a minute without a heart) of which ludicrously over-the-top wire work is just one small part.
To be fair, action movies have been getting dumber, and with more "gimme-a-break" moments worldwide (any British action film starring Jason Statham, or recent Hollywood efforts such as 'Wanted'), still, it leaves one asking do we really need another film in this vein? Movies like Dororo', and 'Hero', are a far cry from the believable samurai pictures of a master like Kurusawa and Mizoguchi.
Still, it's pacing is far better than most, resisting the temptation to have non-stop fight scenes, and a dash of restrained humor thrown in for good measure. And it's fun to catch all the little homages to other films - everything from 'Edward Scissorhands' to 'A Fistful of Dollars'.
If you love the genre, you will love 'Dororo'. If you even like the genre, you will probably really like 'Dororo'. If you don't, it's definitely not going to convert you, and despite it's superiority within the genre, is unlikely to impress you favorably.
