When Paul catches up to Sal in the warehouse, Sal drops his gun, but can be seen reaching from behind his back for a knife. He reaches with his right hand, but throws the knife with his left hand.
It is surprising that the police would have allowed Tommy O'Shea and his men to enter Paul's house to retrieve custody of Olivia's daughter, Chelsea. The police should have acted as go-between, and served Paul with notice that Tommy was taking custody, and have Tommy wait outside.
After Freddie Flakes runs down the garment worker,
the female police officer attempts to stop him by shooting
at his car with her pistol. The bullets create large flashes as she does.
But when the close up of her gun is shown, the diameter of the barrel
shows it to be no more than a .22 caliber at most. A .22 pistol would not create such
large flashing when striking the car and would mostly be invisible.
The flashes were most likely added for dramatic
effect.
When torturing the manager of the factory, Tommy O'Shea uses a pattern cutting machine. This wouldn't work as they have a built in moisture detector that stops then almost instantly.
What might first appear as an error, when Paul opens his wall safe. He only dials 2 numbers. That is very possible, it's commonly called a "night latch". Often people dial the first 2 or 3 numbers leaving the safe to appear to be locked, but by dialing the last one or two numbers, you can open the safe quickly.
Freddie 'Flakes' has a state-of-the-art intruder alarm fitted at his house, but he renders it pointless by running outside when it is triggered by Kersey and making himself a very easy target. However it is within reason that a homeowner would be curious to go outside and see what triggered the alarm, so this is not a goof.
After Paul explodes the soccer ball in Freddie's hands, Freddie is engulfed in flames from the waist up, but after he falls to the driveway, his hair is shown intact, not even singed.
After the "death by cannoli", the front page of a newspaper is shown and "cannoli" is misspelled as "canoli" several times. Also, the article in the paper is just a nonsense paragraph repeated several times.
On the Region 1 NTSC/DVD Widescreen, at 28:48 you can clearly see a Canada Post Gray Mailbox (circa 1995 - Toronto) behind a cement pillar and a US Postal Service Blue Mailbox next to it approx 12 feet away, in the same frame.
An obvious dummy used for the scene where Paul blows up Freddie with the rigged soccer ball.
A few seconds later, after the crate with the body is opened, Sal Paconi picks his pills out of his pocket, takes one and the pillbox's lid accidentally slips and falls on the ground (one can clearly hear the sound). Then he puts the pillbox back in his pocket as nothing had happened.