The movie plays out in the late 30's -- and it shows. Lots of cliches of the era, along with the same visual style. It give the whole movie a strong identity, which I liked.
It's an adventure movie, no two ways about it. You're not going to watch it for the deep characterisation, you won't go to see it for the romantic plot (though there is some romance, but it's barely noticable). No, you'll go see this movie to wonder at the cool scenery, the great gadgets, the Mad Science and the great adventure-movie plot.
Watching this movie is not a life-changing experience, but a really fun way to spend an evening.
When I grow up, I want to be a Mad Scientist too. They get all the cool toys.