(at around 1h 5 mins) When Keith and Gabriel are trying to "crack the code" to the inner vault, on the last digit, Keith tells Gabriel to type "1", and the number reads 827145369, Gabriel stops to think and just as Gabriel type "9", the number now reads 827145396.
During the Vault scene the shots switch between Ripley (Morgan Freeman) and Gabriel (Antonio Banderas): in one shot Ripley's earpiece is in his ear, then it is not, then in the shot following that it's back in again.
When trying to open the vault Martin (Antonio Banderas) looks at his wristwatch twice. The first time the time runs up like in a stopwatch from 16 minutes on. The second time the time runs down like a countdown from 12 minutes down.
When Martin and Ripley are placing the transducer, Ripley is giving Martin directions on how to avoid the sensor waves. Ripley tells Martin to go diagonally left and Martin does that. We can see that Martin is now along the left wall almost touching it. Then Ripley tells him to go straight ahead, the camera angle changes and Martin is in the middle of the corridor moving forward, whereas he should be still along the wall.
When at the party they use the iPhone to see the transmitted video feed from the camera in the buttonhole. In the close up you can clearly see the home button on the left but in the very next scene the phone has turned around.
An ultrasound transducer was placed in the first Vault in order to block the sensors but when the second Vault is open it can be seen behind them that the transducer is missing.
(at around 40 mins) When Martin (Antonio Banderas) and Ripley (Morgan Freeman) are in the subway together and Martin takes out the iPhone to mark the spot on the wall, you can see by pausing the movie that he just clicks on the Photo application and then the lock room's plant suddenly pops up out.
After the alarm went off, several subtitles in English are displayed. One of them is "Yes, in subway. Keep us posted. Out." but instead "Keep us posted" head of security actually said "Stay at your position".
When Ripley (Morgan Freeman) and Gabriel (Antonio Banderas) are talking on the rooftop you can easily see in Gabriel's sunglasses the microphone and the cameras.
Subway scenes (supposedly in the New York City subway) were filmed in the Sofia metro, with Soviet-made 81-714.4 subway cars.
(at around 1h 25 mins) Towards the end when the S-class Mercedes pulls up to the jet, the licence plate is a US plate but the Merc is a Euro model with larger licence plate backing and no US-spec lights. Evidently filmed in Bulgaria.