The recent return to theaters in 4K is something of a gimmick – I honestly couldn’t discern any improvement in the picture quality – but truthfully, any opportunity to experience this excellent crime noir on a large screen is welcome. When "Brigid" (Mary Astor) contacts PI "Sam Spade" (Humphrey Bogart) and his partner "Archer" (Jerome Cowan) with a suspicious tale of her sister’s abduction by an older man, they are immediately skeptical; however, $200 (and some attention from “Archer” for the lady) convinces them to proceed. They were correct in their initial assessment: her story was full of inconsistencies, though not so many as to cause "Archer" to meet his end, and soon Spade and the police find themselves pursuing/evading a killer while attempting to uncover a reason behind it all. The film’s true highlights for me are “Joel Cairo” (Peter Lorre) and “Gutman” (Sydney Greenstreet), the exceptionally shady pair; Gutman is an affable gentleman who holds most of the puzzle pieces together, possessing both charm and a dangerous cunning. Does "Spade" unravel the mystery before he becomes a casualty? The film stumbles here – the plot lacks genuine suspense, and the final fifteen to twenty minutes feel hurried and underwhelming. Bogart delivers a fantastic performance; his character embodies a wonderful cynicism, that of a man who's seen too much, taking his first drink of the day from the same glass he used the night before, and Astor is competent, though not particularly captivating, in her pivotal role. Eighty years have passed, and I still maintain that the powerful score by Adolph Deutsch, some truly atmospheric lighting and effects (there’s a considerable amount of rain!), and, naturally, a strong cast with an engaging narrative remain difficult to surpass.

Source on TMDB