Here's a sample of some of the cosplay on hand, with photos from Gigazine, Akiba Blog, Otaku.com, and Asagawo Blog. Some of the most interesting cosplay were the ones in which characters were reworked or reimagined entirely. That straight up Raiden ain't half bad, either.
Click each image to expand to full size.
ワンダーフェスティバル 2013[冬] の男性＆ネタなコスプレイヤー [アキバBlog]