The sign on Aziraphale's shop reads: "Bookshop Opening Hours - I open the shop on most weekdays about 11:30 or perhaps 10 am while occasionally I open the shop as early as 8, I have been known not to open until 1, except on Tuesday, I tend to close about 5:30 pm, or earlier if something needs tending to. However, I might occasionally keep the shop open until 8 or 9 at night. You never know when you might need some light reading. On days that I am not in, the shop will remain closed. On weekends, I will open the shop during normal hours unless I am elsewhere. Bank Holidays will be treated in the usual tradition, with early closing on Wednesdays, or sometimes Fridays. (For Sundays see Tuesdays). A. Z. Fell, Bookseller.
Playing on the television in the cafe where Crowley and Shadwell meet is Witchfinder General (1968), which is spoofed by this series' ineffective Witchfinder army.
David Tennant (Crowley) complains about having to watch a performance of William Shakespeare's 'Hamlet.' Tennant himself famously played Hamlet both on stage and in Hamlet (2009).
The Narrator uses the expression "the reason people in Times Square can't see America." In the original source novel, the phrase was "people in Trafalgar Square can't see London."
Crowley and Aziraphale as knights: "I'm here spreading foment." "What is that, some kind of porrige?" Frumenty was a very common wheat or barley porrige in medieval Europe. It has been called 'England's first national dish'.