When Mr. Phelps turns the tape player on, paint tubes that lie beside the tape player are lying diagonally beside it. When he turns it off, the paint tubes are lying perpendicular to it (possibly to conceal a tube to emit smoke for the tape's destruction effect).
When preparing to kidnap Constantine, Barney climbs into the crane and you can see many tall palm trees. There are no palm trees in what is supposed to be an Eastern Block country.
When Constantine (actually Stravo) fires at the mirror, the gun is aiming at the bottom of the mirror, but the hole appears in the top half.