Toward the end, when Willy had the "Hotel" hallucination in the Chop House bathroom, Stanley comes in and finds him on the floor, seated beside a toilet with his drink on the cover. In the VERY NEXT moment, when the camera cuts back to Willy, the drink is gone.
In the scene where Willy comes home in the beginning, look at the ceiling in the kitchen when he is yelling about not having oak trees, you can see the other buldings.