That sucks that you didn't make top three. Being a competitive cosplayer can be really frustrating sometimes, especially since judge bias makes it into their decisions frequently, despite their best efforts. I honestly see no flaws in your construction, you really do deserve some sort of award for that. Your stockings, for instance, were hand made!
Critique? Hm... I can't really see your wig clearly, so I can't figure out its styling too well. I don't know much about faux-leather, but I'd try to starch it or stiffen the sleeves a bit, since they're pretty crinkled at the elbows and cuff openings. Plus, starching or interfacing and stiffening the cuffs would make the beautiful hem decorations stand out. Really, other than that.... there's not much to honestly critique without closer inspection.