This is one of the best films I have seen in a long time. Adrien Brody is sensational as Jack Starks and that is the key to the success of the film.
As to the question of whether it is all just a dream: there is nothing in the film to suggest that, so why should anyone arbitrarily decide that to be the case. A story is what the writer wrote: no more and no less. Time travel to the future is currently impossible, both technologically and logically (the future is a concept based on prediction and speculation of events that have not yet occurred and may never occur, thus, it never actually exists). That, however, does not mean it doesn't ever happen. Should that be the case, our whole notion of existence and reality (as well as cause and effect in this case) must change - that is one of the basic ideas in the film.
So, if you just watch the movie very carefully, you will see a very interesting, mind-challenging, well-produced story. Then, if you wish to add more in your own mind that is your prerogative.
As to the question of whether it is all just a dream: there is nothing in the film to suggest that, so why should anyone arbitrarily decide that to be the case. A story is what the writer wrote: no more and no less. Time travel to the future is currently impossible, both technologically and logically (the future is a concept based on prediction and speculation of events that have not yet occurred and may never occur, thus, it never actually exists). That, however, does not mean it doesn't ever happen. Should that be the case, our whole notion of existence and reality (as well as cause and effect in this case) must change - that is one of the basic ideas in the film.
So, if you just watch the movie very carefully, you will see a very interesting, mind-challenging, well-produced story. Then, if you wish to add more in your own mind that is your prerogative.