When Tom first enters the Car Rental shop looking for Angela, after a shot of his stun gun the camera goes to a shot of Tom as he walks across the lobby of the shop. You can very clearly see the shadowy reflection of a crew member in the window behind Tom moving around.
Angela's BMW had an outdated New York State license plate. The Red, White and Blue with Statue of Liberty graphic was phased out in 2000. All of the other cars in the film had the correct (and current) blue and white NY license plate which New York required all vehicles to change to by 2002. Because many of the cars shown in the film were 2005 or later models the film was set in at least 2005 so there is no way her car could have still been using that style of NY license plate.
Near the beginning, Angela comes around a corner and bumps into one of the security guards and calls him by his real name (the actors name) rather then his character name but calls him by his character name later on at the desk when she is waiting for the cab.
When Angela is fighting off and killing the dog in the car, the retractable rear passenger seat-belt is directly behind her back and completely shielded from the blood spatter except for perhaps the top few inches. After Angela kills the dog and eventually steps out of the car, the seat-belt becomes visible and it's covered in large, soaked-in, blood spatter spots all the way down, where her body was shielding the dog's blood spatter throughout the entire scene.
When Angela stub the little stuff to Tom's eye, He close his eye while the stubbing. After that we can see he fully opened his eye and the eye ball is nearly out of it's hole. When he pull out the little stuff from his eye, after that it closed again.
When Angela is first put in the car to go for a ride as Thomas puts it, you can clearly see her hands fidgeting in front of her. But the shot before that has Thomas handcuffing her hands behind her back.
In the beginning when she's trying to use her cell phone, it clearly says "Telus" on it. Telus is a Canadian cell phone company that doesn't provide service to New York City. Technically she could be roaming, but it seems unlikely.
When Angela stops the elevator, Thomas uses a fire hose to flood her elevator car. When Angela reengages the elevator car, you can see the water draining out of the car as it drops from the outside. In reality there is plenty of room on all four sides of the car for the water to drain down. The elevator car would not have filled up with water the way it did. The water should have drained out the storm water drain at the bottom of the shaft.
The goof item below may give away important plot points.
When Angela stabs Thomas with a fork the wound instantly pours blood. Then when the fork is removed the bleeding stops. (General First Aid practices suggest if you find someone with a knife still in them, leave it there. It may prevent further bleeding.)