- Awesome, Dear Boy: Lee Grant had been a big fan of the first film and enthusiastically jumped at the chance to appear in the sequel.
- B-Team Sequel: The film was made without the original director or screenwriter. Richard Donner was busy directing Superman, while David Seltzer wasn't interested in doing a sequel. Years later, he commented that if he had written it, he would have set it the day after the first film ended, with Damien living in the White House.
- California Doubling: The scene that's supposed to take place in New York is still actually Chicago. It's filmed in Chicago, southeastern Wisconsin and Eagle River, Wisconsin, which is in the northern part of the state.
- Executive Meddling: The director wanted Damien to be fifteen, according to Word of God. He wanted this because he thought it would be interesting to give Damien a girlfriend before he discovers what he is, ensuring Angst when he has to chose love or destiny. The execs forced him to accept Damien at 12. It's very ironic that nowadays the execs would be pushing to have Damien older.
- No Stunt Double: Lew Ayres performed most of the stunt of his watery death himself up until the point where his character disappears under the ice. Lee Grant tried to persuade the veteran actor not to do it but he was determined to give it a shot.
- Old Shame: Lance Henriksen didn't like the final film at all, and he said it didn't help his career much either. He didn't get along with Don Taylor and found the shoot very miserable as a result. (He was hired by the original director Mike Hodges who got fired).
- Orphaned Reference:
- Ann's HeelFace Turn as the Whore of Babylon and ultimate demise was part of a scrapped plotline involving Damien's love interest that would've held the latter as a Red Herring accidentally killed because of this.
- The explosion at the climax that kills Ann and burns down the museum was originally foreshadowed more, and subsequently seems to come out of nowhere in the final film.
- Damien's temporary angst at discovering his true nature was meant to the central conflict of the film, but was ultimately all but dropped except for two brief scenes.
- Wag the Director: Original writer/director Mike Hodges was constantly embattled with producer Harvey Bernhard, who rewrote large portions of the script without first consulting him and overruled many of his creative decisions. The conflict was further accentuated by Hodges taking several hours to film fairly innocuous shots, including spending an entire day's location shooting in order to get a flag to flutter in the wind properly, and Hodges eventually left the film to be replaced by Don Taylor.
- What Could Have Been:
- David Seltzer, the writer of the first film, expressed initial interest in a draft treatment that followed young Damien living in the White House after having been adopted by the President as shown at the end of the first film. He ultimately chose not to be involved in the sequel, and his ideas were scrapped, though some would later be used in his miniseries Revelations.
- Damien was intended to be several years older, with his increased awareness of his true nature as an allegory to puberty and self-discovery, making the film a sort of twisted Coming-of-Age Story. His angst would've served a more prominent part in the narrative.
- The reveal that his adopted mother was the Whore of Babylon an Orphaned Reference to this earlier plotline, in which Damien would've had a girlfriend and been forced to choose between her and his destiny, with this dichotomy providing film's central conflict. His girlfriend acted as a Red Herring, with the running implication that she is the Whore and her being killed by Richard Thron under this pretense only for his wife to reveal her true allegiance and perform a HeelFace Turn in a Twist Ending. As such, there was meant to be more animosity from Damien to his mother, which would run counter to the mother's own doting and protectiveness toward her ward.
- Sgt. Neff was originally supposed to be a mentor figure to Damien, the proverbial "Devil on the Shoulder" to drive him toward becoming the Antichrist, approximate to Mrs. Baylock in the original film. His role was significantly whittled down after original director Mike Hodges was replaced by Don Taylor, and his character is reduced down to the bare minimum.
- Neff was originally meant to be one of dozens of disciples who would give Damien assistance and fulfill his needs, including being directly involved in the deaths of anyone standing in his way.
- A longer climax was originally scripted, in which Richard survives his initial stabbing and fights back at his wife, inadvertently triggering the fire that kills them when they are both trapped inside the collapsing building by Damien. This ending was trimmed due to safety and budgetary concerns.
- Many of these changes were a result of Creative Differences between original writer/director Mike Hodges and producer Harvey Bernhard, which eventually led to Hodges being replaced and the existing script being heavily retoooled.
Trivia / Damien: Omen II