The Players of Inception
The Extractor - The extractor is a master con man, a person who knows how to manipulate a dreaming mark into revealing their deepest mental secrets. At heart, an extractor is a classic con man - he creates a false set of circumstances that manipulate the mark into revealing his secrets. Cobb (Leo DiCaprio) uses the same type of con man repertoire as George Clooney in Oceans 11 - only Cobb knows how to literally do his work on a subconscious level. Fancy premise aside though, the extractor (as I said) is basically your classic con man.
The Architect - The architect is the designer of the dream constructs into which an extractor brings a "mark." Think of an architect as a video game designer, except in this case they create the "levels" within a dream, complete with all the aesthetic and tactile details. The mark (also known as "the subject") is brought into that dream construct and fills it with details from their own subconscious and memories, which convince the mark that the dream the architect built is real - or at the very least, is the mark's own dream.
The architect can manipulate real-world architecture and physics in order to create paradoxes like an endless staircase, which makes the dream world function as a sort of maze. The dream is constructed as a maze so that A) The mark doesn't reach the edge of the maze, realizing that they are in an imaginary place. B) So the mark runs the maze, leading the extractor toward "the cheese" - i.e., mental secrets the mark is protecting.
The Dreamer - The architect and the dreamer are not always the same person. The architect designs the dream world/maze and can then teach that maze to a separate dreamer. The dreamer is the person whose mind actually houses the dream and it is the dreamer's mind that the subject/mark is ultimately brought into in order to to be conned by the extractor. The dreamer allows the mark to fill their mind with the mark's subconscious, and unless the dreamer maintains the stability of the dream, the mark's subconscious will realize it's been invaded by foreign mind(s) and will try to locate and eliminate the dreamer to free itself.
When you start getting into the whole dream within a dream aspect of the movie, identifying the dreamer can be tricky - this is especially true when Cobb and his team start running their con on Fischer using three separate levels of dreaming. Once the tri-level dream sequence starts, one good way to keep track of the dreamers is by noticing which team member stays awake and doesn't follow the team down to the next level of dreaming - a dreamer can't enter a lower dream state, otherwise their level of the dream would end.
Here's a rundown of who is actually dreaming each level of the Fischer con:
- The rainy city - Yusuf the chemist (Dileep Rao) is dreaming this level. Yusuf is drinking a lot of champagne in the "real world" on the plane, so when he goes to sleep he has to pee (hence the rainfall). Since Yusuf is the dreamer of level 1, he has to stay in that level of the dream, hence why he has to drive the van.
- The hotel - Arthur (Joseph Gordon Levitt) dreams the hotel, which is why he has to stay awake when the rest of the team goes down to the snow level. When the van Yusuf is driving goes off the bridge and is flying through the air, Aurthur's "body" is suspended in air, which is why gravity in the hotel level of the dream goes haywire - as the dreamer's body is shifted and moved, it affects the physics of the dream he's dreaming, since the mind (and inner-ear) is registering the change in gravity.
- The snow fortress - Eames the "forger" (Tom hardy) is dreaming this level of the dream. A question has been raised about why the gravity in the snow world doesn't go haywire when Eames' body starts floating in the zer0-gravity hotel. Well, you could say that Eames' body isn't being shook up or shifted in any way his mind (or inner-ear) would actively register or that being so deep in a dream state cushioned Eames from the effect of gravity. Or, you could say that it's a glaring plot hole. Truthfully, it's questionable.
- Limbo - Limbo is actually unconstructed dream space - a place of raw (and random) subconscious impulse. Ariadne drops a line early on about the fact that the extractor team can bring elements of their own subconscious into the dream levels if they're not careful, and since Cobb has spent time in Limbo and has a raging subconscious, the Limbo space they enter includes his memory of the city he and Mal built for themselves.
If you're more of a visual person, Cinema Blend has put together a handy graphic detailing the different levels featured in Inception:
The Mark - The mark (Cillain Murphy) is the person who the extractor and his team are trying to con. The mark is brought into the mind of the dreamer, and since the mark is unaware that he/she is dreaming, they perceive the dreamer's world as real while simultaneously making it feel real to themselves by filling it with details and secrets from their own subconscious. The extractor uses those details and various mental prompts to steer the mark through the dream world maze, towards the mental secrets the extractor wants to steal.
As stated, the mark thinks he is still awake, perceives the dream world as real and reinforces that notion by "projecting" his conscious view of the world onto the dream - this is why projection people populate the dream cities, etc. Because of the extractor's manipulations, the mark goes along with the faux reality of dream, ultimately reaching the point where they either realize it's a dream, or open their mind and reveal their secrets.
Projections - Dreams feel real to us when we're dreaming and part of the reason for that is our mind's ability to construct a faux real-world setting for us to interact within dreams. Often, that dream is something like a city or any populated area which has other people walking around it. In Inception, those people that the unknowing mark populates the dream world with are known as "projections."
As is explained in the film, projections are not part of the mark's mind - they are manifestations of the mark's vision of reality. If a mark has been trained to defend themselves against extractors, they have a part of their subconscious which is always on guard against mind-crime in the form of militarized security which attack mind invaders. In Cobb's case, Mal ("the shade") is a projection based on his need to remember his dead wife. Mal wanted Cobb back in limbo - his own subconscious trying to pull him back to a place where he could "be with her."
The Forger - As in "forgery," Eames (Tom Hardy) is a master of imitating people's handwriting, mannerisms - and in the dream world, even their very appearance. This is key to Cobb's plan: on dream level 1 (the rainy city) Eames impersonates Peter Browning (Tom Berenger), Robert Fischer's closest advisor.
Using Browning's image, Eames subtly suggests things to Fischer that fools Fischer into creating his own subconscious version of Browning (seen in dream level 2, the hotel). The version of Browning Fischer conjures in his subconscious motivates him to run deeper into Cobb's maze (dream level 3, the snow fortress) in order to find "the cheese" - i.e., the inception of the idea Saito wanted Cobb to plant. Basically, the Forger fools Fischer into using his own subconscious projections against himself.
Mal (and her shadow) - Mal is the character who acts as a vessel for all the more complex notions and questions about reality the film raises. Mal not only thought but felt that the world she and Cobb had built in limbo was real - it fed her emotionally and made her happy. When Cobb planted the idea that "Your world is not real" in her mind, he only meant for it to wake her from limbo. Instead, what he actually did by allowing that idea to take root in her mind was to destroy that sense of fulfillment and connection she once had - and once it was destroyed, it couldn't be repaired.
Even with her husband and children all back together, Mal couldn't access that emotional reality that comes with the bond of love and connection to our love ones. Because of inception, Mal couldn't value love or connection the same way because a fake reality only offered fake connections and emotions - only she and Cobb and their love was real to her anymore. She needed to keep trying to reach some higher state where the nagging doubt would be cured and she could be happy again. And so, thinking Cobb lost in a faux reality, she arranged the hotel suicide and murder implication in order to force Cobb to follow her. The idea Cobb implanted in her led her to her death (seemingly), and the guilt of that act led Cobb to create a shadow of her in his subconscious.
At the climax of the film, Mal throws deep questions at Cobb (and the audience) asking if having faceless corporations chase somebody around isn't yet another dream state. She questions the very nature of reality for all of us and certainly whether or not the faux reality of film isn't its own sort of dream state - a place where fantastic things occur - an imagined place we as movie goers share and perceive differently and fill with our own subconscious views and interpretations. Pretty deep meta-thinking stuff.
Well, as an answer Mr. Nolan, I can say: only when a movie like Inception comes around to light that sort of spark in our minds. Seeing Clash of the Titans wasn't nearly as thought-provoking, fun or worthwhile. :-P
STILL confused about the characters, who's dreaming when and what the levels of the dream (and how to kick out of them) are all about? Check out a second handy infographic, made by Deviant Art user "Dehahs".