Corrected entry: When Evan is playing the guitar for first time in front of Wizard and the others, Wizard is wearing a white shirt, but when Evan and Wizard are talking looking at the stars, Wizard's clothes are different.
Corrected entry: Because of his despair for losing Lila, Louis does not play his guitar for eleven years. When he decides to start playing again, he takes out his guitar and plucks every string. His guitar is perfectly tuned, and this makes no sense. As I am a guitar player myself, I know that if you go so long as a month without touching your instrument, it will go severely out of tune. And he didn't tune it off camera before he did this, as we see him open the dusty case for the first time in a decade and play the strings immediately afterwards.
Corrected entry: It seems to be early spring in Washington Square and high summer in Central Park throughout this movie! There are virtually no leaves on the trees, forsythia are blossoming in one scene and it is even snowing at one point. However, every time you see Central Park, whether it is during a "fly over" scene or during the concert at the end of the film, it is high summer with all of the trees fully in leaf, audience members viewing the outdoor concert in shirt sleeves, and soloist, Keri Russell, wearing a bareback, halter-top gown.