When Stupe and Lucy visit her sister, the film playing on the TV in the background is an early short film by the directors.
The promotional poster art depicts an American flag with 6 stars crossed out (although 7 states are stated by Lt Brewer as seceding and 2 more on the verge), the crossed out stars represent the seceding states of Texas, Louisiana, Florida, North Carolina, South Carolina, West Virginia and Georgia as well as Maryland and Pennsylvania being close to seceding.
Most of the movie was shot in Ridgewood Queens, not Bushwick Brooklyn.
In the beginning of the movie on the train platform it says Church Ave but in reality Church doesn't run through Bushwick and that stop on the L train is actually Jefferson St.