The uniforms that the Japanese soldiers wear is inaccurate, given that the movie takes place in the years 1936-1937. The Japanese Army did not wear their rank insignia on their collars until May 1938; until then rank was displayed on the shoulder. Also, their shade was a bit darker khaki than what is depicted in the movie.
A song performed in a night club early in the movie is the original Cninese (Mandarin) version of what became an international hit for Frankie Laine in the early 50s under the name of "Rose Rose I Love You". The original was written in 1940, while the scene was set in 1937.
When Todd is proposing the job to Sophia he says, "It's up here. The bar, everything. It's all inside." When he says this, the camera is from behind him and two fingers are briefly shown pointing to his temple. The camera angle quickly changes to show from the front and only one finger is at his temple.