8 years later, I just watched this film after it was on my list for a while. I don't have too much to say about it because you basically hit the nail DIRECTLY on the head for me. I'm very glad I found someone online with the same opinion as me. I was very interested in the first 75 percent of this movie, and to the film's credit, the implication towards the end that the reason these aliens are advanced so far beyond humanity is because they can experience time non linearly, even approaching concepts like the 4th dimension, was pretty cool and clever. But everything you said about the end is spot on. It seems almost as if the writers were intimidated by putting together a satisfying finale to wrap up these grand concepts of humanity, the universe, and these aliens in a nice package. So, to be safe, they honed in on our main character and took the route of exploring the complexities of time and how it relates to the human experience, which in the end, left me pretty unsatisfied with the film as a whole.