When Arlen first tries to sell books to the bookstore he is taking a different number to or from the cart or counter each time the camera leaves and returns to his character (takes two but has three and visa versa).
When Arlen has the girl attempt to sell one of his used books the girl looks directly at the camera for a brief second.
In the scene where Arlen has the girl attempt to sell one of his used books the girl looks directly at the camera for a brief second.
After Arlen puts the 45 record on, he jostles the stereo when he has his first back spasm. The needle clearly bounces off of the record but the music continues playing. After he falls to the floor, a close up of the record still playing is shown.