The word means the mixing of steam engine victorian setting and punk rock of the 80's, it's developed a bit from that but essentially its a genre of alternate history. It takes the idea that steam engines became the main source of power rather than electricity so everything still has a very grundgy look to it, with copper and brass being the main construction tools and cogs and wheels being used so often it's pretty much to the point of decoration. The clothing is all reminiscent of the Victorian era, through corsets, top hats, blouses and bonnets.
While the genre is growing in popularity from conventions and costuming into movies, books and as mentioned video clips it still isn't common place and it a bit of a geek sub-culture.
So those are my problems with the film, what is it I like. First off the designs are pretty spectacular, I really would have liked to see more of them but they give a real sense of wonder to the movie. The 2D animation is top notch as always for Disney cinema releases. The real strength in this movie comes from something that Disney is not known for, and thats character and relationships. This movie feels like your watching real people and not fairy tales and thats incredibly rare for Disney. When Disney changes the original source material it's to make it more child friendly, to make it safer. In Treasure Planet they have the father of the hero Jim Hawkins leave when he is a child. Not die nobly, not pass away off screen but leave. This integral change made the story more focused on the relationships which are done perfectly. Jim is played off as an intelligent but rebellious misunderstood boy, and if I read that I would have rolled my eyes. There are few character descriptions more overused than that apart from wise, mystical mentor figure doomed to die. However they handle it well, you can see the Jim's acting out does come from an actual place of pain and he does allow people to change. He's not a rebel just to try and appear cool. Giving the character father issues does also play into the relationship he has with Captain Silver, you see how much they go to care for each other. You believe their interactions and the ending is more satisfying because of this and reminds me of the same kind bitter-sweet closure you get at the end of Aladdin and the King of Thieves.
Fighting against nostalgia, as this is one of the few Disney movies I didn't see as a child, I find it sitting in my top Disney movies of all time. Not a hundred percent sure where it exactly fits in a list but perhaps that's something I could look at for future posts. But regardless of that this is a movie that is really worth a watch. 8.5/10