While Taggart is in the mayor's office, not only does the blanket move on its own, it also changes color from plaid to white & back to plaid again.
When Billy is shot at as he is leaving the real estate developers office the bullet shatters the back windshield and leaves a clear exit hole in the front on the passenger side. During the brief chase sequence directly afterward the the hole in the front is missing
When Billy and the mayor are in the mayor's office where he first hires Billy to investigate his wife, the decanter and the glasses on the table and the blanket on one of the couches all change position repeatedly between shots.
(at around 1h 25 mins) Billy leans on and breaks the wing mirror on his assistant's car. As they drive away from Todd Lancaster's place, the mirror is fine.
While Taggart is in the mayor's office, the camera circles around to reveal a stopper that keeps magically popping on and off the Scotch decanter in plain sight.
In Jack Valliant's elections headquarters there's a poster with the Hebrew word for "Jewish". Though those are the correct letters of the word, they're written left to right instead of right to left (hsiwej).
The cheque given towards the first and the last installment of the hiring fees of Billy Taggart have the same number 984523706.
The first $25,000.00 check shows "Void if over $1,000.00" below the amount. The "second" check shows the same on one ripped piece.
When Billy puts the document in the photocopier to bring down the mayor he puts it in upside down.
There is a shot early in the film looking south down P
ark Avenue where it clearly shows the " Pan Am" logo on what has been the MetLife Building since around 1992. Looks like the film makers relied on some old stock footage rather than have a second unit shoot any new street footage for the film.
We see a banner that marks the Chinese new year, however the film takes place around October 29th 2012. The Chinese new year is at February.
Exterior and interior shots show that Paul Andrews is inside Grand Central Terminal. He purchases a ticket to go to Montauk, however, there are no trains presently going from Grand Central to Montauk. Andrews then boards what is clearly a Long Island Rail Road train (a sign is outside), which does service Montauk. But then Andrews would be boarding at Penn Station, not boarding an outside station that appears to be on Long Island.
The secret "contract" that the mayor was trying to hide was Articles of Incorporation for Rochway, Inc. These would have been public records filed with the state and very easy to discover.
When Billy decides to scan the "contract" so as to make it ready to send by email, he doesn't flip and so scans only the back of it.