I really like this shot. The emotion is apparent and compelling; the lighting and color of the subjects is pretty good. Definitely one for the wedding album.

I like that the background is apparent, only slightly out of focus and underexposed. I get a sense of the context without being overwhelmed or bothered by it; had the background been more well lit, I would have noticed the empty chairs and all the people not paying attention to the first dance, and the unfortunate exit sign might have become more apparent. As it is, it does not really attract my eye until after I’ve digested the main subject.

However, it does suffer from that chronic problem of wedding photography — black tux and white dress. His tux has gone largely to black and fades into the background without definition; it’s tough to keep definition in both the dress and the tux. Always better to err on the side of the dress, IMHO, as you’ve done. Both his and her hair have some of the same issue, to a lesser degree.

Not bad for head-on flash. Doesn’t look too flashy, and probably about the best you can do under the circumstances, at least without an assistant carrying a wireless slave flash on a pole.

Nice shot. I might be inclined to play a little with white point, black point, and contrast curves to see if I can get more definition out of the tux, but otherwise I wouldn’t change a thing.