(82 minutes in) When Bob is running out of the building after talking to Maurice, he removes his tie as he descends the stairs. In the next shot, however, his tie is once again tied around his neck.
When Bob looks at the Hula dancer figurine, the co-worker behind his back is constantly changing. First, nobody sits behind him, then a bald headed person sits there. Then nobody sits there. Then the bald headed co-worker sits there again.
After Bob first backs out of shooting, he empties the six shells of his gun into a small bowl in his drawer. The next day when he goes to reload the gun, there are only four shells in the bowl.
The cartridges that Bob loads into his revolver are real, but the primers are indented, indicating that the rounds have already been fired.
When Bob goes to lunch, he carries his briefcase by the handle, then sets it down flat on the top of the wall. When he opens the case, the items inside are perfectly arranged.
When Bob is asked up to Gene Shelby's office to meet the grief counselor, Gene asks him if he wants something to drink. "A Pepsi, or something?" The cans on the table however are Coca Cola.