The address on the envelope sent by Irena changes from the incorrect "Toronto, NO" to the correct "Toronto, ON" when delivered.
After Irena leaves a secret message on a tray of hors d'oeuvres, she places a napkin on top of the tray. Although untouched, the napkin disappears and then reappears on the tray.
The ITARA Rolodex card is pinned to the map a few shots before it is stolen from the UAN office.
The postal code of "52 Bay Street" would start with M5J not M6O.
Just immediately after William step out of Kasia's car (after the evening in bar, he offered her to drive car for her), he walks on the right side and Morawska on the left. But if it would be in Poland, he should drive the car on the left position, so after he parked the car, he would step off on the left side.
In the climax of the film, Billy Ray does a forward roll before opening handgun fire on the bad guys. The slow-motion used for this highlights the fact that a stuntman or double was used for the roll.
Just before the "sword scene" when Steven kills the top bad guy, they both have guns pointed at each other. When they both decided to put the guns down you can hear the bad guy de-cocks his gun, even though that type of gun has an internal firing pin and wouldn't make that kind of noise.
When William kills the top bad guy at the end and there is a blood trail from the dead bad guy to him, you can see the camera scrolling over the blood on the blood.