Like some of the other reviewers, I came upon this film completely by accident. And like one other reviewer, I planned to watch about 10 minutes and watch the rest another time. But the movie pulled me in and stayed with me until the end.
It's a most unusual time-travel story. Although some of the concepts have been used before, this takes them in a different direction. It's a quiet, slow-paced movie, so if you're looking for quick action, you'll find it in short supply. But the atmosphere is as important as the plot progress and the dialog. It reminds me a little bit of David Gerrold's "The Man Who Folded Himself".
If you're looking to settle down and watch something out of the ordinary -- and you're willing to give it your attention and accept its pacing -- you'll find it very rewarding.
