When John Cusack checks into room 13, the desk clerk tells him that it is NOT an interconnecting room. When they're hiding in room 14, Robert De Niro crashes through a door and tells him "Lucky there are interconnecting rooms"..
When John Cusack is speaking to the agent, the chain is on the door, then disappears and then reappears.
The broccoli on Robert DeNiro's plate (on the plane) changes positions several times.
A million dollars in cash weighs 20 pounds, gold even more. Five million dollars would not be easy to carry.
When John Cusack pursues Robert DeNiro into the woods, he holds the gun in his left hand as his right hand becomes his wounded hand in this short sequence. The mistake becomes very obvious when looking at the mirrored text on his baseball cap.
After they come back from the bus stop and into the motel room, the phone rings. The desk clerk is 'dead'; who put the call through to the room?
Rebecca Da Costa is woken in the bath tub by John Cusack. He tells her about the death of his wife, she has a big bruise on the side of her forehead, the bruise then changes to the other side of the forehead.