Lighting changes significantly compared to other shots in the shot where Detective zips his jacket. Ironically, the whole purpose of the shot was to eliminate other continuity error - jacket zipped/unzipped through the scene.
Vito's cell is not quite realistic in details, especially the lock.
When Olena Miloslavskaya delivers her only line in the movie you can hear in the background the original variant as it was dubbed.
Random female voices can be heard in the background in the Warden scene (they're also credited as an in-joke).
Seen in the window behind the Detective in Burchill scenes there's a parked VAZ-2121 "Niva" car, which is very unusual for USA where the movie takes place.
Behind the Detective in Burchill scenes are clearly Soviet radiators which are unusual for USA, where the film takes place.
Burchill has one of the buttons on his shirt unbuttoned for an unknown reason.