When Paul is looking at his bank statement, the total line says "$2,000,00.00" which is missing an extra 0.
(at around 1h 09 mins) As Clifford is bringing a drink to Bob, the glass appears empty. When Bob picks up the glass (prior to throwing it), the inside of the glass has been partially coated with an amber material to make it appear to contain liquid.
When Paul speaks for the first time with the 2 fathers his voice is scrambled, to prove he has their kids in the basement he holds the phone near Dean, Haily and Bob, their voices can be heared normally, no scramble of their voices.
At the end when the Dynans drive by the gas station where Paul's 2 dead partners lay, we see a Canadian speed limit sign of 80 KMPH. Though the movie was shot in Canada, it was set in the USA.