My rating: 3 of 5 stars, might get bumped higher upon second viewing...
This is a time travel movie, but very different from others I've seen. It really deals with many of the actual limitations on time-travel that the laws of physics imposes, which I found very refreshing. It is really brilliant the way they dealt with the [TECH] issue that so many episodes of Star Trek suffered from.
I might need to watch this again just to grasp all the plot points though. Sometimes it was hard to tell who was when, and the plot is extremely twisty, a necessary evil. This story is hard to tell. I kind of wish I had a diagram or something to help me grasp all the little turns.
I gather that this movie was on a budget of $7000 and won an award at Sundance. Very impressive. There aren't any flashy special effects, but it really didn't need them. Be prepared to be confused, though.