I agree with others who have expressed that this feels more like the beginning of a TV show than a movie. It definitely left me wanting more. I enjoyed the movie the whole way through although a few of the moments meant to build suspense were a little obvious. I actually give them a lot of credit for making it still feel like anything could happen even though you know they have infinite re-do's as long as the machine stays on. People saying this isn't cerebral I think have overlooked several things. Maybe it's just late but my brain is left searching for answers and I'll share a little bit of what's going through my head.
My theories on a few things:
First, I think that somehow when the machine is touched it affects the loop and perhaps creates a loop within the current loop. The fact that at the end of the movie they finally see the same crack in the screen from the video they found earlier indicates that most of the movie was a loop within a loop. I think they have exited the loop in the final waking scene but they must still disable the machine this time around in order to exit the main loop. The interesting thing about the loop boundary is that time will be passing normally outside the loop. One odd thing is that the bad guys repeatedly call to outside the loop for backup. It seems to me that if the outside world isn't effected by the loop, than they would be aware of every time the call was being placed. Also, if the loop was being played out thousands of times, than years could have passed outside. I guess the inverse is also possible; that as time is looping at increasing speeds on the inside, that virtually no time is passing outside. Or the outside could also be reset by the machine and the boundary is caused by the loop within the loop. If that were the case than a call to the "outside" is perhaps just going up one loop level. Regardless, it still doesn't quite add up.
I'd love to have a few of these questions answered in a sequel. The movie was well made and the acting was pretty good all around.
Review by Nathan from the Internet Movie Database.