As a huge noir fan, I had been wanting to check out this film, which is practically a love letter to the genre. I wasn't disappointed. The height of noir films seemed to be in the 40s/50s, but it turns out the 70s grit is a good fit.
Like many noir films, the plot itself can be a bit of a labyrinth, and you have to make sure to memorize the names of the various characters, but that's part of the fun.
Art Carney plays a grizzled old detective well, and Lily Tomlin is the quirky sidekick who could have been super annoying, but is somehow endearing. They make for a fun duo.
The film isn't perfect, and probably won't do much for people who don't care for noir, but it's a winner to me.