Factual errors: During their first djembe lesson, Tarek tells tells Walter to stop playing a 4/4 rhythm. However, even though Tarek talks about playing a 3/4 rhythm, they play a 12/8 rhythm. However, this could be 3/4 as 12 is divided into groups of 3.
Crew or equipment visible: During the night shot of Manhattan from New York Harbor, the wake of the camera boat is visible in the lower left hand corner.
Revealing mistakes: As Mouna (Hiam Abbass) and Walter (Richard Jenkins) are becoming closer, Mouna calls Walter Richard - his real name - rather than the character's name.
Continuity: When the student comes to Walter's office to hand in his assignment, the first shot of the student standing in the doorway next to the bookshelves shows a book called "Numerical Recipes," which is a well-known text in computer science and, thus, rather out-of-place in Walter's office. In all subsequent shots the books are more in keeping with an economics professor, suggesting a re-shoot of the first scene.
Revealing mistakes: There is a drop-bolt lock on the inside of the entrance door to Walter's apartment building, but there is no corresponding latch on the door frame.
Factual errors: In New York airport, the flight was announced as "flight to Syria", although it should actually name the airport (Damascus), not the country. But more importantly, there is no direct non-stop flight from New York to Syria.
Revealing mistakes: When Walt and Mouna return from their evening on Broadway, he remarks that it's 12:30 (presumably at night), however the window behind them clearly shows daylight shining through the vegetation.