Character mistake: When John meets his clone in the rundown house he lives in, the clone has a British accent and tells him his story. John has an American accent. When the real John tells him "I'm not like you, I had a wife, a family, a daughter" he mistakenly uses a British accent.
Character mistake: In the very first scene, in the first shot you see a sign in Spanish that says "NO PASE por orden del departamento de arquiologia". The correct Spanish word is arqueologia.
Character mistake: Amber was a poster artist and Ben was a musician. Amber said to Serena, "You know a lot of people and can afford rent, so why do you want to live downtown?" The downtown area or center of a city is especially attractive to artists (as Amber should know) for its art/cultural/entertainment opportunities and experiences. Amber was also implying that it was more expensive to live in the suburbs than in a downtown apartment (where rent can be unaffordable to all but at least the upper-middle class). (00:07:20)