Kelly Vint Castro played the young Catherine Langford in the original Stargate movie from 1994. Footage from that movie is used at the very beginning of this movie. She returns to the franchise here in a small cameo playing "American Agent".
The film takes place in 1928 and 1939.
28:00 Catherine explores the event horizon the same way Daniel Jackson did in the movie on the first trip.
At 3:43 there is what appears to be a Channukah menorah on the table between the Langfords.
At one point the German leader refers to the woman photographer as Eva. Eva Braun was the girlfriend and then wife of Adolf Hitler.