Factual error: When Art buys a soda, a close-up reveals the quarter he uses is not a pre-1998 US Quarter (George Washington bust on the front, eagle on the back), nor the 1976 Bicentennial version, but appears to be one of the 50-states series of 1998-2008 quarters, most likely Oregon (which happens to be the state where the filming was done). (00:26:00)
Factual error: When Richard asks Art his opinion of his book, a copy of "Haymarket Scrapbook" is on a shelf. This book was first published in 1986, yet Richard's book will be published in 1981. (01:03:00)
Continuity mistake: In 25 years neither Richard, Art, Chris nor Nikos age. They all look exactly the same throughout the movie.
Visible crew/equipment: At the end of the movie, Richard exits his car to eat pancakes with Art. The boom mike is reflected on the door, including the operator's hand holding it.
Visible crew/equipment: When Christine drives to pick up Richard to take him to the music show, a boom mike is visible on the car's door.
Factual error: In the Vietnam scenes, the helicopter had a wire cutter (a prominent forward-leaning blade above the windshield), but they weren't in use on military helicopters of that era.
Factual error: During a scene from 1978, Richard's taxi has the third brake light in the rear window, but those lights weren't introduced until 1986.
Factual error: When driving in Portland in 1972, many newer buildings in downtown are visible, including the US Bancorp tower, which was constructed in 1983.
