Neo-noir is slightly darker than noir, but neither has any consciousness that justice will be done. In neo-noir, the world is just a shithole (pardon my language) and the characters are just trying to get through it all. Often the protagonist gets away with the crime. Movie buffs with recognize this in Point Blank or Blood Simple. Some say that Chinatown is the greatest neo-noir movie, and another says that it is one of the “greatest, most stylish films ever made.”
If you want a send up of noir and neo-noir movies, watch Kiss Kiss, Bang Bang from 2005. It has all the noir characteristics and is funny to boot.
Here is the article about noir fiction in the Huffington Post. Penzler closes his article with these words: “I love noir fiction. It makes doom fun. And who doesn’t like fun?”