At which dream level did Inception end?

Could there be a possibility that Cobb's mentor, Mal's father, purposely trapped him within the maze as revenge for his part in Mal's suicide?

I can only offer my own personal observations on this theory, and if it's true then maybe the story isn't about one man incepting another, but about his own personal inception. In thematics, it might make sense: just as Mal was made to believe that her reality was an illusion, Cobb was made to believe that the illusion was his reality.

It could also be argued that he is still dreaming because of the thematic space, in which Christopher Nolan occupies Cobb in. His character is usually associated with large castles or buildings that overlook a lonely sea, but in the 'real world' he is mostly associated with vast, winding, decaying metropolises. So if the end of the film is reality, then how is his setting that of a rural, seaside home.

Answering directly, I believe that Cobb isn't in any specific level of dream, he's simply lost in the vast maze of his own consciousness. He's simply trapped within his own world, lost to reality after what he reaches what he thinks is his goal.

But it could also be argued that he was in the real world because of the children's ages. If you stick around for the credits, you can see that two sets of children were used to act out James and Phillipa. But it's simply a technicality, the film achieves a lot more deph if Cobb is stuck in the dream. If he had been 'incepted'.