This is the first appearance of Mulder's parents.
To create an unique and otherworldly sound made by the weapon used by the hunter, several sound effects were considered before co-producer Paul Rabwin voiced the noise himself on a microphone.
This is the first episode with the Alien Bounty Hunter.
Scully's line "someone fired more shots at the White House" is likely a reference to Francisco Martin Duran who fired 29 rounds from a semi-automatic rifle at the White House 3 months before this episode aired. No one was injured. Duran later claimed he was trying to save the government and the world from an alien threat. He was convicted of attempting to assassinate Bill Clinton and sentenced to 40 years in prison.
The first time that Mulder's dad is seen he is smoking, just like the first view of the Cigarette Smoking Man in Pilot (1993).