Tracy's apartment was not a set. In order to get the desired view though the windows, it was specially constructed at the top of the famed Clocktower Building in New York. Cimino says in the commentary track how proud he is to be the first (and likely only) director to get that view of the New York skyline. "I can't stand going to a place and shooting it the way everyone's shot it before. People go to Paris, there's always the Eiffel Tower. They come to New York and it's The Plaza Hotel and Central Park. So I wanted a view of the city which would be unique and memorable."
Michael Cimino was officially allowed final cut of the film, but was forced to make one change to the ending. "The only change they asked me to make, which to this day I still find inexplicable because I think it sums up the movie, was to the very last line. At the end of the movie, there's another fight that breaks out on Mott Street, during a funeral parade. Mickey is in the middle of the mêlée, Tracy runs in and picks him up off the ground, they both look like survivors of a war. The camera closes in. If you look closely, you can see that they're not saying the line that you're hearing. The last line of the movie was, Stanley looks at her and says, 'Well, I guess if you fight a war long enough, you end up marrying the enemy.' Oliver Stone himself is married to a Vietnamese girl right now. I'm sure you'll see American's with Iraqi women at some point. For reasons that I can't understand, that line was not acceptable, so I took a line from some other place in the movie and I slipped it in and it doesn't make any sense at all. But that line, that sums up the whole movie."
When it was released, most American critics gave the picture a negative review. Cimino notes in his commentary track, "Interestingly enough, one of the few positive reviews we got was from someone who generally hates all my work, Sheila Benson. Because she's married to a Chinese man. And she wrote a very interesting reaction to this, because she was stunned at seeing things that she knew were real. See the one thing Sheila Benson got was the exploitation of Asians, by Asians. Of Chinese by Chinese, and that, she said, was the first time she had seen something like this."
According to Mickey Rourke, the part of Stanley White was written for Clint Eastwood or Paul Newman who both turned the role down.
The exterior shots of New York City were actually sets built in North Carolina. Said sets proved realistic enough to fool even Stanley Kubrick, who attended the movie's premiere. Co-writer/director Michael Cimino actually had to convince the Bronx-born Kubrick this film's exteriors were shot at a sound-stage and not on location, 8. While set primarily in New York City, much of the film was shot in North Carolina including the sequences on the streets of Chinatown. They recreated streets with attention to detail up to and including the angled grade of their Mott Street -- the "main" street in NYC's Chinatown -- which is not actually flat. They took plaster casts of curbstones and recreated the grade for authenticity, something he says most NYC reproductions on film don't achieve. "If you look at Ragtime, it's flat, and that's why it doesn't look like New York [City]. It's a very rocky little island." He's proud of their accomplishment as it even fooled Stanley Kubrick. The legendary director was given a screening in London where he told Cimino that "Chinatown looks so great." Cimino told him the truth, and after a little bit of back and forth Kubrick realized he'd been duped. "If you can fool Kubrick, who had the best eye in the world, you can fool anyone." The sets have been reused in dozens of films in the years since.