Bad. Terrible. Awful. Repugnant. Unacceptable. Stupid.

Rating: 2/10 (21 June 2011)

OK so Gyllenhal is good in this movie. Lets get that out of the way first. Now onto the roast.
What a terrible steaming pile of dung this movie is. It simply makes NO sense. Lets examine the two possibilities for the "world" that they are operating in.
In the first, they have developed code that allows them to put a person's consciousness into the body of someone else in a mock-up of the world as it was at that time an infinite number of times. Fine - Where did this mock-up come from? They implied that it was from the the guy who Gyllenhal is inhabiting, but the train exploded... his brain would be peanut butter (along with everyone else on that train). OK so lets say magically his head got tossed away from the train and they retrieved it, how exactly does this guy manage to have complete knowledge of everything that exists in that world? He didn't go into the bathroom and open the ceiling and find the bomb there, so there would be nothing there in his version of the world. He either got off the train or stayed on it, so there's no way he could know what happened after the point that the train moved on. He might continue to believe that the Middle- Eastern stereotype guy was the terrorist - there's no way he could have any knowledge of what happened after those two events diverged. So of course, the virtual world example is ridiculous and makes no sense.
Alright so what about the idea that it is an alternate reality? This is even harder to believe. If its an alternate reality then of course there is no way to believe that the events would have unfolded in the same way as in the reality the movie takes place in. Every alternate would be different and none would reliably provide information about the reality of the movie. The guy that Gyllenhal "inhabits" maybe doesn't even exist in the alternate reality. Maybe he died of cancer. Maybe he works in Japan. Maybe he called in sick today. Who knows???
If its a virtual construct then all the information is already there, just parse the data. If its an alternate reality then by the definition of the word ALTERNATE you can't rely on it being even marginally similar to your reality. And if its time travel you could literally send him back an infinite number of times in succession. Just by the odds you would eventually get the data you needed by reading his brain (which is silly by itself, don't get me started...)
And then there is the annoying obfuscation that moves the plot along but is entirely unnecessary for the movie. There's no need to hide facts from Gyllenhal's character -- Just tell him what he's doing! There's no need to get his permission -- Just send him back! Why the writers play these stupid games with their audience I haven't a clue.
Stop being stupid movie-going zombies! Be critical! Ask questions!
If you keep consuming this kind of crap and saying its a filet mignon, the studios will continue to feed you CRAP.