Plot hole: Tom told I.D. Halden, "My grandmother passed a few years ago and we inherited the family house." If there was a mortgage, who was paying it for a couple years? And if the house was inherited, there would not be a landlord, they would not be paying "rent", and owners do not get served with an eviction notice. (There was no mention of a legitimate reason, such as unpaid taxes.) There's a failure to discern home ownership (with a mortgage) from renting a house (which is not "inherited").
Suggested correction: It seems to be that it is about two different houses, the rented one they already live in, and the inherited one which is renovated.
Revealing mistake: Late on in the film; Arnie and the female officer kick in the door to one of his teams house. Unfortunately Arnie is in his 70s now and not as agile as he used to be, the door was open and simply pushed hard. Look at the door, it has no damage and neither does the frame. Also, the door barely opens past a hard push. As tactically trained operatives they would not have pushed the door if it was ajar either, they would have opened it slowly to avoid startling anyone inside and warning them.
Continuity mistake: During the early part of the movie, the left rear door of Doc's car is dented. For the rest of the movie, the dent is gone.
Factual error: When the guy is talking to him on the phone and the Russian smashes it on the floor, the phone smashes and the battery comes out but the guy other end can still hear him. (01:04:00)
Character mistake: Near the start, there's a misspelling of the word "Victim" in the newspaper heading "Police expect Beadie to mail latest victim's ID." Read by the man at the bar who is smoking a cigarette. (00:02:14)
Continuity mistake: Treat Williams is drinking a brown liquid from a glass (scotch?) while accusing Gina Carano of having something to do with his son's disappearance. Shortly afterwards, the liquid is a different color and the glass is much more full. (00:41:40 - 00:42:40)