Gaffes

When Splitface begins fleeing from Tracy in the middle of the movie, he is driving a black early 1930s era automobile through a residential area. However, when the chase continues through the city, Splitface is driving a gray late 1930s era automobile. When Splitface exits his automobile shortly thereafter, it is the black early 1930s era automobile again and this is the car he drives for the rest of the picture.

The angle and curvature of the scar on Splitface's cheek changes from scene to scene.

Nightclub owner Steve Owens (Morgan Wallace) disappears half way through the film and his character's relationship to the story is never adequately explained; his daughter, Judith Owens (Jane Greer) is also abandoned without any explanation of her involvement in the proceedings.

The matchbook advertising Owens' restaurant puts an apostrophe in the wrong place, so that the possessive case of his name reads Owen's, not Owens'.

Obvious mannequin Splitface throws through the skylight.

When Splitface gets out of the car and runs around the corner Tracy has not arrived nor is he close enough to have seen where Splitfaceran, yet he magically knows exactly what direction he ran even what building he ducked into.

Dick Tracy says a murder was committed with a kind of knife that morticians use to perform postmortems. Morticians don't perform postmortems unless they are also coroners, and a police officer like Tracy should know that.