Indeed, it is sometimes easier to identify steampunk elements in an artwork (be it visual, audio, animated or functional), rather than labelling the entire thing as steampunk. Of course, for some people steampunk is a process or a way of thinking and behaving, which is even harder to define.
I like to think that trying to define anything that is punk, is itself not punk as it implies a structure and formality that punk tends to react against. This is true, regardless of the type of punk.
Sorontar