I'll put my faith in every other major film critic, the writer/director, and stars on whether it's a Noir or not. And, it is....I don't think everyone's wrong.
I've read that one of the chapters is subtitled, "The Lady in the Lake" which is a famous Chandler story, they speak in stylized Noir manner, it's violent as hell, has a narrator, and is a hardboiled detective story. It definitely sounds like a comedy Noir and those are always more light in tone.
http://www.metacritic.com/film/titles/kisskissbangbang
Sorry to come off like a hardass on this particular issue, but I'm only going by the huge amount of text that has been written about it. Shane Black set out to write and direct a Neo Noir, and as I said it looks like that has what he did, although it may not necessarily conform to the usual standards. There are many different kinds of Noir..some barely conform to what you would normally look for.
Saw Saw II. Nice and bloody, and a better film than the first if that means anything with this sort of movie. I liked it and would recommend it to gore hounds.
