Got shot at Yusuf's dream, carry on in Arthur's dream and then of course then in Eames. But he bled to death (isn't it) in Yusuf's dream that follows up to Arthur's dream and Eames. So when Cobb finds Saito when he is at an old age... whose dream is that?!? Is it limbo?!?

Got shot in Eames dream and to discover him in Cobb's dream... that is logical because of Mal

Mal exist in Cobb's dream... but that is not Mal. That is actually his guilt. There was a scene that explains about dreams and sub-conscious minds. We do know we can never control our sub-conscious minds and from what the film was saying that it brings out our guilt that we can't control. Hence, Cobb was pretty much an emotional wreck after he did his 'first' Inception - which is to his wife. The guilt that carries in him is implanted in his sub-conscious and whenever he can't control these things (basically his sub-conscious), Mal appears.

Now the levels in the elevator I felt were memories he kept and the basement was his worst guilt memory of what he had done to his wife. That memory alone is what he felt for Mal, that the Inception he planted in her is what he knows the real truth that Mal became vengeful and hence, killing whoever and whatever that the sub-conscious knows about Cobb's work. In the dream sequence of each level, the children and Mal appears because after all, he was the architect before and that is what and how he can shape things but not realizing it was the guilt that does it that he can't control - hence the sub-conscious mind.

At first I did think Mal was in limbo but actually she is not. She died in the real world and of course, it does explain how Cobb became a fugitive and he had to run away because Mal was already unstable but manage to pull it off that she is sane.

is in limbo, how the heck did Cobb find him even?!?

did Cobb find him in Limbo? To be in limbo, isn't that like completely unreachable... I mean, it's limbo. And how the heck did they get out? Didn't they say it could take days, years concept?

like The Matrix Revolutions - remember how Neo was trying to get out of the train station? He ran one way and came out the other side but in the same station?