I watched the movie in a very coherent state of mind and used a fair amount of concentration. I still can't figure out what the hell happened at the end.

The totem continues to spin at the end and the fact that it cuts off while the totem is spinning means that he is still DREAMING and that he is still in a dream. This leads me to the ultimate question of -- whose ******* dream is he in???

The ending makes the narrator un-credible starting at the beginning of inception but potentially from even any of the dreams prior to entering the inception mission.

One thing I know for sure is that he CANNOT be in Limbo, by logic. We know that to get into limbo, you just have to die. But apparently it's not the only way in because Leonardo and the architect girl used the sleep machine in stage 3 to enter Limbo. I know they entered Limbo in stage 3 because they were trying to get Fisher and we know that means they have to go to Limbo because Fisher died and if you die, you go to limbo. However, it seems that to get out of Limbo means you just have to die -- because the architect girl and fisher jumped off the building and died, which brought them back to life across all stages. BUT, for some reason Leonardo didn't/ couldn't do the same? WTF? Okay, so he wanted to retrieve the Japanese guy who was lost in Limbo because the Japanese guy doesn't have a totem and couldn't have known he was dreaming, but then how does this lead to him being stuck in a dream at the end?

I'm ******* mind boggled out of my mind.

A friend of mine said she watched the movie stoned and it made so much sense. Screw her!!!

I think the whole movie is about Cobb's struggle to make up for the initial inception that shattered his soul. I guess it all started with his father, who, as far as I could tell, was a pioneer in work with dreams. Cobb wants to live up to his father's accomplishments, as many male children do. It's a poetic non-coincidence that he is sent on a job to get another man's son to reject an inherited empire.

That's the shortest way I can phrase the complex thoughts regarding the main point of the film.

Other points:

- The wobbling totem implies a return to reality, as does the fact he sees his children's faces. What is certain is that he now inhabits a realm of his choosing.
- After Ariadne shoots Mal, Mal's shadowy face seemed eerily similar to Ariadne's. I find it a little odd that Cobb's father basically handed Ariadne to Cobb. There is a clear parallel between the two women. Why else would Ariadne be so interested in Cobb's subconscious?
-Saito is older than Cobb because time moves slower as they reach deeper levels of the dream state. Saito got to limbo before Cobb, so it makes sense that by the time Cobb catches up to Saito. That's Relativity.
-Cobb hooked up to the machine frequently because his non-dream "reality" a. sucks and b. is not a plane of existence in which he feels he can confront, sort out, or understand his demons. Think of it as a drug addiction.
-Cobb and Mal are young on the train tracks because, well, it's a dream. They don't have to be old, right?

Cobb was MUCH younger than Saito so that makes sense that Saito would be way older in the beginning/end of the movie.

Cobb hooked up to the inception machine so that he could "relive" his lost life with his wife, Mal...

the entire movie was designed to be a dream, for us the audience, we are thrown into it randomly and not sure how we got there (i.e. the opening scene) and we believe that what we are seeing is our reality (at least for the length of the movie (i.e. "really getting into the movie")...we are forced to believe what we see is their reality throughout the movie and we "wake up" when the credits roll...and we never get to find out what happened in the end...just like when you're dreaming and something amazing is about to happen, and you are woken up by an alarm clock or a noise of some sort or even another person, or possibly biologically/naturally...

Inception is a movie about making movies. It's the attempt of a movie director to make a movie which is the perfect vision of its creator.

At the cinema, the lights go down and the audience shares the director's vision, like a shared dream. The whole movie is allegorical, with the following symbolism:

His "real" children represent the films he's made, he wants them to be perfect. They are the goal he is seeking as the end to this "dream".
Mal, his wife, represents the Muse, his own selfish passionate vision which he must overcome in order to effectively connect with the audience.
Saito represents the studio executive the director works for.
Arthur, his sidekick, represents the film producer (reason, experience, conscience) who's working with him every step of the way through the production.
Eames, the forger, represents the actors and their daring, playfulness, invention.
Yusuf, the technician, represents the production designers.
Ariadne, the young girl, represents the writers -- craft, curiosity, and intuition.

He uses all of these to temper and ultimately defeat his own vision, Mal, so that he can successfully plant an idea into Fischer's mind. Fischer represents us, the audience. We are the ultimate target for this inception (placing the idea in our minds during this "shared dream" that happens in the theater that it was a good film). Note that in the scene where inception takes place, Fischer is the only one present.

In the end, Cobb doesn't care whether the top is spinning or not, because it doesn't matter. The film has been released (it is now one of his children that he is united with) and he has to take a leap of faith that it was the best representation of his vision.

They left the totem wobbling for the sequel.Simple as that

I also enjoyed this movie to watch it twice. After the first viewing I had many questions, after the second I take the narrative straight forward to avoid confusing conundrums.

To try an answer your questions in the context of the movie -

1) I think the train recollection was Mal's within the movie narrative. As a projection of Cobb's subconcious guilt she not have the memory of them growing old together, since his guilt was projecting her as she was when she died.

2) Cobb says it's the only way he can be with his family/wife/children. Also the chemist in Mombasa, when they take the crew into the basement says for some people it is the only was they can dream. Cobb is a highly skilled extractor and thus is more apt to know when he is dreaming (although he spins the top several times in the film). For Cobb to actually dream he needs to be sedated (use the machine).

3) I agree with the answer above. Saito was older to begin with, plus he also died what say 10 minutes before Cobb jumped into limbo. That minutes could be decades (Although Cobb has a confused look and seems unsure of his purpose until Saito and he talk leading to believe that Cobb was also there for decades...)

4) One thing I read is that when Cobb is in the dream state he always has his wedding ring on. When he is in reality he does not. It's fun to look for it through scenes in the movie. I take the last scene as reality, although throughout the film there are enough clues to question it. If Cobb is dreaming throughout the film and thuse all characters are projections or people inserting themselves into his dream, why would he have Mal trying to trap him further into Limbo and why have Ariadne constantly trying to save him. You can build assumptions, but any off screen narrative is an assumption that the movie narrative is not accountable to.

Also I think as they descended into Fisher's subconcious they were in different dreams right? Ariadne built the dreamscape, but the snow dream was actually Yves' dream (i think from the dialogue Cobb says this dream is your Yves, and there is another reference in that sequence too i think). So they were falling asleep, digging into their subconcious in someone else's dream. trippy.

Anyways, great film. I thought it was phenomenal.