Visual symbolism in Pacific Rim. Also: stuff falling.

I've head a lot of chatter about the "visual language" in Pacific Rim and how most of the movies smarts are in its visual intelligence. There's a lot of hidden visual motifs and symbols just under the surface. For instance, the blue highlights in Mako's hair becoming more prominent after we learn her backstory. One thing that stands out to me is the ubiquity of things falling. Not just the constant rain, but if you look for it, you'll see it all throughout the film: sparks falling, ash falling, snow falling. There's hardly a scene where something isn't "raining" in some proverbial way, even in the scenes that don't take place outdoors. Do you think there's any meaning to this, or am I just seeing things? Also, what are some other visual language and motifs you've noticed in Pacific Rim? (holy crap, that ending sounds like the prompt for a college English course essay... I assure you, this is not homework. :P)