"Forget it, Rick; It's 2019."

Rating: 7/10 (15 July 2012)

First off, this review uses parallelism between Chinatown and Blade Runner and includes spoilers for both films. As such, please stop reading if you do not want knowledge of important plot elements of either of these films.
Chinatown is a film that sneaks up on you and punches you in the face at the end. But it does it in such a way that -- for a moment -- you're not even sure what happened. Nicholson, Dunaway, and Huston play their parts brilliantly. It's truly painful to watch Evelyn fall from such a stoic person to a nervous wreck. All the while, she keeps you guessing. In fact most of the characters of this film keep you guessing in an Agatha Christie sort of way. Who's good, who's bad, who's crazy? It keeps shifting on subtle levels.
The cinematography is excellent. Nice smooth camera shots and composition. Restrained use of camera motion. Nice editing and a suitable score. The pacing is also really good. Fast enough to keep a person's interest, but slow enough to show the lush locations and buildings. The only case in which I'd subtract marks is for the Chinatown location itself. Once Chinatown is shown, it's presented fairly flat and lacking in visual detail.
After watching this film, I couldn't help but think of Blade Runner. Now I see the connections between the two films. Blade Runner owes quite a bit to Chinatown. In particular, Rick Deckard's interaction with Rachel. I can also see why Jeter's truly awful and inconsistent novelized sequel to Blade Runner (The Edge of Human) made sexual abuse references in regards to Rachel. However, dealing with the sudden shock of discovering that you're not human serves the purpose effectively enough. Adding on a borrowed element from another film on top of that is totally unnecessary.
The tone of Chinatown and the visual style of the era that it is set in forms the basis of Blade Runner's world. 1940s future-noir is the look, and the tone is equally serious. This 'tone' is something that a great deal of modern films seem to lack. Both films hold true to their tone and mood consistently while presenting a story that could be applied to various eras.
Before beginning to think that one film is copying another, consider that most art forms derive elements from earlier works. There's no question that Chinatown owes quite a bit to 1946's The Big Sleep. And I'm sure it continues on back beyond that point in film and novels. The key is how it's done:
In particular, if a writer or director has a new idea and is inspired by an existing film, then it's best if the new project be a unique world with new characters. In other words, not a sequel. In this case, Chinatown to Blade Runner. In cases such as this, scenes and characters can be similar. Even lines of dialogue can take on somewhat similar structure.
However, if a sequel is to be shot then the rules change. The viewer is much more wary of sequels and prequels. Unfortunately, there has been a rash of sequels lately that recycle lines wholesale. To re-use general plot points is one thing (and to be done subtly -- if at all), but recycling lines is often the kiss of death for a sequel.
Examples:
Strong Sequels:
Aliens: This film uses a plot structure that is very similar to that of Alien. However, it works because the two films are of different genres and the characters are unique enough between films.
Star Trek II: The Wrath of Khan: In this case, there was an imperative to take the film in a different direction from the first. Hence this film is very different from Star Trek: The Motion Picture. It represents a completely different story, totally different motivations, mood, and plot. The two films share little in common, except for the general universe in which they exist and the main cast of core characters. Ideally, this is how a sequel should be done. Note that it does remain consistent to the previously-established Star Trek universe.
Star Wars: The Empire Strikes Back: Again, the film is unique from its predecessor. Furthermore, it falls into a slightly different sub-genre of film. The tone of Empire is much different than that of A New Hope and remains consistent throughout. Consistency is absolutely key to making any film a success. Hopefully modern directors can re-discover this concept. The screenplays are totally unique between the two films and there are no recycled lines of dialogue.
I won't name sequels that are considered to be poorly done. I'm sure readers of IMDb reviews are well aware of many examples of sub-standard sequel and prequel films. Take a look at them closely and look for recycled lines, 'homage' scenes that are nearly carbon copies, blatantly re-used plot lines, weak and highly derivative stories, inconsistent treatment of firmly-established characters, and a lack of substance.
All of this returns us to Chinatown. Here is a film that is packed with emotional substance. It's subtle yet strong. Chinatown owes its visual style and tone to the film noir era while presenting totally new material. The characters are multi-layered and difficult to strictly classify. It never tries too hard and there seem to be no absolutes in the film. And lastly -- and most importantly -- it ends exactly where it should. Perhaps the ending should be the starting point of any writer's work. It's what makes or breaks films with even the greatest level of potential.