It's a solid film that holds up reasonably well over time, though I don’t share the extreme praise many critics and audience members have offered. It’s clear the performers are enjoying themselves, which makes this classic movie worthwhile in its own right. The writing is superb; it’s something I try to achieve myself in my novels, however modest they may be. I struggled with Sam Spade's detached demeanor when he received some difficult news early on and his reaction to it. He did manage to partially make up for that at the very end during a brief, intense speech about partnerships. Also, the conversations concerning romance between Sam Spade and Miss O’Shaughnessey struck me as absurd because I never observed any genuine connection or intimacy between them—to say nothing of their plotting against each other. If I may be so bold, Sam, I thought your assistant Effie was more attractive, kindhearted, and a better choice for you. Despite this, the movie is enjoyable to watch, and Mr. Spade’s resolution of the mystery at the end is exceptionally well done. The actors in smaller roles are perfectly adequate. Try to identify the actor who played Bert the cabdriver in *It's A Wonderful Life* ("My mouth’s bleeding, Bert! My mouth’s bleeding!”). And if you pay close attention, you can notice Humphrey Bogart subtly curving his lips—the same mannerism comic performers often amplify when imitating him. There truly is only one Humphrey Bogart.

Source on TMDB