You know The Maletese Falcon, with Humphrey Bogart?
Did you know that it wasn't the first movie made from that source material?
Yep! In fact, it was the third.
The first was made in 1931, pre-code. It's got a "lighter" tone and a "loser" pace, and a bunch of pre-code elements (it talks about stripping, makes some sexual references, makes oblique references to several characters being homosexual. )