During the first car chase (with the white van), Bean straps on a police helmet for his safety. In the very next shot of the car, Bean isn't wearing the helmet.
Before the car crashes into the wall, in long shots the driver is seen wearing a shoulder belt, but shots inside the car show him without. Immediately after the crash into the wall, the driver has a shoulder belt but the next shot inside the car shows him without.
At the bowling alley, Freebie de-cocks his semi-automatic pistol twice while getting ready to enter the restroom.
When Freebie and the Bean lose the head-on collision battle with the van, their crumbling Ford then makes a right turn down a wrong way street, and collapses on the right-hand side of the street. In the next shot, the car is way on the left and even next to another car which wasn't there previously.
During the motorcycle chase sequence, virtually no attempt is made to disguise the fact that a stunt driver is substituting for James Caan. The double's face is seen clearly in numerous shots.
The boom mike is visible when Freebie and Bean pay a visit to Meyer's home.