Steampunk is so awesome because the elements of the genre are things we love on their own, and when they come together... well I don't think I need to say how good it is, do I?
It's the love of clockwork, simple enough for you to be able to mess with it with a novice's ability but complex enough to amazing things.
It's the effect of things being made for practicality only but still giving off a sense of fashion. You see it in the way a clocks gear work together when it is working properly, you see it in a steam train waiting at a station with it values bellowing steam and smoke. And you, definitely, know what I talking about when you see a hot girl with bulky googles and a tool belt strapped on whilst she messes with some engine.
It's the idea that you create something amazing with just a brass, pistons and some bolts, and you done have to care how it looks as long as it works.
It's the idea that every machine around can easily be tinkered with (come on you mad mechanics you know you want to).
It's the risk that steam and gears can harm you at any second and that society isn't caring enough to add health and safety features, you can be killed by whilst working here, you can be hurt if you don't stay on your toes and figure out how things work.
It's the industrial revolution effect, massive changes are happening, technology coming into a world where no-one even seen it before. The Crossing of two completely different worlds.
Steampunk is the beauty of practicality along with crude and simple things, and how they come together to make Amazing things happen!
And I sincerely hope developers can pay proper respect to this otherwise I coming for them with a wrench and a revolver!
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( I edited the girl bit sooooo many times as, well, this isn't a Fantasy thread!)