Viggo Mortensen claims that, prior to shooting their scene together, Christopher Walken ate several whole garlic cloves.
The film was originally filmed in 1993 and released two years later in 1995. This was the Weinstein's M.O., as they would film a movie before editing them, reediting them, and finally releasing them a year or two later.
The writer/director is also the writer for the original Highlander film in 1986. Similar themes can be found between the two movies. Immortals at war for centuries, they wear trench coats, and both stories begin near the climax of the much longer history of the characters.
According to a story related by the DP:
One night during shooting of the climactic scene on top of the desert bluff, the driver was taking the DP and Amanda Plummer down from the bluff location on a winding road. The shoot was on Native American land and the tribal authority was very concerned about conservation of the location, so much so that Plummer had taken the DP's and driver's hands and spoken a spiritual prayer that they might be safe and not do any harm to nature along the route.
Reportedly, the van pulled out onto the road, got up to speed, and promptly struck an owl that swooped out of the night and exploded across the front of the van, much to the shock of the occupants.
When upon finishing the location shoot the DP and director were discussing with the tribal leader what damage the shoot had inadvertently caused and how it might be settled, the leader was reportedly easy going about it, explaining that all is fixable, not anything sacred. "It's not like you've killed an owl or anything."
Per the story the DP and director basically just nodded agreement and walked off, not saying a word...
Colonel Arnold Hawthorne is played by Patrick McAllister. Due to the nature of his role and the long gap after It's Alive (1974), McAllister is not credited, but he appears as "special thanks" for his collaboration in the movie, credited as Patrick Kerlee McAllister.