Strangers On a Train (1951)

In Alfred Hitchcock's thriller - an adaptation from Patricia Highsmith's first novel about amoral murderers who 'traded' or 'exchanged' crimes:

• the opening sequence introducing the duality of the two 'strangers on a train' with their distinctive contrasting shoes:
  
  - Bruno Antony (Robert Walker), a villainous psychotic homosexual
  - Guy Haines (Farley Granger), a pro tennis ace
  
  
• the conversational scene of Bruno's hatched plan to "swap murders" - Bruno would kill Guy's wife (Guy wanted a divorce in order to marry Senator's daughter Anne Morton (Ruth Roman)), and in return, Guy would kill Bruno's tyrannical father; Bruno was very direct about human nature: "My theory is that everybody is a potentiaI murderer. Now didn't you ever feeI like you wanted to kill somebody?"; he then proposed his plan: "Two fellas meet accidentally, like you and me. No connection between them at all. Never saw each other before. Each one has somebody that he'd like to get rid of. So, they swap murders....Each fellow does the other fellow's murder. Then there's nothing to connect them. Each one has murdered a total stranger, like, you do my murder, I do yours...For example: your wife, my father. Crisscross"
• the film's key object (or MacGuffin) - Guy's monogrammed cigarette lighter (a gift from Guy's girlfriend Anne to him, with the inscription "A to G" and a symbol of two criss-crossed tennis rackets) - Guy mistakenly left the lighter on the train during his hasty retreat
• the many strikingly visual and auditory scenes in the amusement park stalking and murder sequences, including the foreshadowing scream in the river-cave tunnel just before the scene of Bruno's murder of Guy's stifling, vulgar and promiscuous wife Miriam (Laura Elliot) - the strangulation murder scene was reflected in Miriam's thick-lensed glasses that had fallen to the grass on "Magic Isle," while in the distant background, the amusement park's merry-go-round ironically played "And the Band Played On"
• the famous scene during the playing of a tennis match, when Bruno in the stands was watching tennis star Guy straight ahead of him (on the sidelines) as all the others watched the game
• the society cocktail party scene in Senator Morton's (Leo G. Carroll) house, when Bruno jokingly demonstrated how he could simply murder someone by strangulation and actually began to uncontrollably choke one of the elderly matron guests Mrs. Cunningtham (Norma Varden)
• the cross-cutting between the scene of spectators watching a vigorous Forest Hills tennis match (Guy was attempting to win it quickly - he was literally playing against the clock, in order to stop Bruno from framing him and planting incriminating evidence against him on the amusement park's "Magic Isle" island, the location of Miriam's murder) and the scene of Bruno's frustrating struggle to retrieve the film's MacGuffin - Guy's cigarette lighter - that was accidentally dropped down a sewer drain grating

The MacGuffin - Guy's Cigarette Lighter in a Sewer Drain

• in the finale set at the amusement park, the intense wrestling scene between Guy and Bruno aboard the revolving out-of-control carousel, after the merry-go-round operator was accidentally shot by police and fell on the controls; as Bruno died after being crushed by the wildly-spinning merry-go-round, his hand opened to reveal Guy's lighter - leading to Guy's exoneration

Struggle Aboard Merry-Go-Round	Bruno's Dead Hand Opening to Reveal Guy's Lighter