Near the end, when Jim and Sara are being pursued by Dirk, the weather changes from shot to shot, alternating between shots of bright sunny weather and shots of dense dark fog.
When Jim and Sara flee Jim's car as they are being pursued by the motorcycle the stunt woman playing Sara has a fuller figure and bounces noticeably as she runs.
Reading the newspaper clipping regarding "The Underground Railroad" rock group, the article below the headline went on about OPEC and the oil crisis which had nothing to do with music or rock groups at all.
The newspaper clipping that Rockford holds up at 25:36 about the "Underground Railroad" and the clipping that Rockford holds at 26:38 while he is on the phone with Becker are two different clippings. The first clipping has "Underground Railroad" spelled out on a single line while the second clipping has "Underground" above "Railroad" printed out.