When Praxas grabs scythe to use it as a weapon the blade moves like it's rubber, compared to a real one.
A lapel microphone taped to the inside of actor Robert Wagner's karate uniform shirt is clearly visible for about two seconds. This is at the end of the scene when he is questioned by the detectives at his karate class.
When Stone and Keller first arrive at the house of Gregory Praxas the camera pans down and the boom operator can be seen hiding behind the wall to the left of the front gate.
A radio dispatcher describes a suspect vehicle as a 1970 Dodge. It is actually a 1969 model.