Franchise Original Sin: Many criticisms hurled at the Genre Throwback to Film NoirThe Black Dahlia can actually be found in this - an overly convoluted story and a lot of information that's hard to hold onto. The difference is of course that The Big Sleep still has a lot of merit with regards to how well it pulls that off - whereas The Black Dahlia was a three-hour movie cut down into a confusing two hour length.
Narm: The Adaptational Modesty to Carmen when Marlowe interrupts her photoshoot. It doesn't quite have the same effect when she's wearing such a modest nightgown.
Marlowe requests that the bookshop girl take her glasses off while they share a drink. This would be considered quite rude today.
Marlowe also wears sunglasses to pass himself as a pretentious literature professor to Agnes - effectively invoking Nerd Glasses. Sunglasses had only just become available to the public in 1937 and hadn't caught on as a cool fashion accessory yet.
Values Resonance: Marlowe's efforts to stop the lewd photos of Carmen being made public is still very relevant today, given the scandals involving female celebrities having their private photos stolen by hackers.
Marlowe and other characters are open with their disgust for homosexuals. They freely use homophobic slurs like "queen" and make jokes at their expense. After getting decked by a gay man, Marlowe asserts that it didn't hurt much because gay men "have no iron in their bones."
Geiger's pornography business is an underground criminal enterprise, and Marlowe is thoroughly disgusted by it.