Brainy, technical, and talky, this low-budget sci-fi movie breaks the rules of storytelling; it's deliberately confusing, but its absolute confidence makes it all the more alluring and fascinating. Written and directed by Shane Carruth (who also produced, edited, composed the score, and acted), Primer runs a "B"-movie length of 77 minutes, but it's a dense 77 minutes. The dialogue sounds ultra-naturalistic, sounding like engineers and businessmen in meetings, and it's easy to miss something, although not everything spoken is essential, either. It's not a casual movie, and not for everybody, but highly rewarding.
There are no visual effects, no depictions of what it might look like to travel through time. In truth, there's quite a lot of time spent sitting around and waiting. Nevertheless, Carruth builds tingling suspense throughout, mainly because of the way Primer feels absolutely real, as if this stuff could actually happen, and because of the intriguing sense of the unknown. The organic, edgy sense of science at work -- Carruth studied mathematics, rather than filmmaking -- make it seem as if this is a movie that needs further study. And indeed, it does hold up to (and demands) multiple viewings, and each viewing brings a startling new revelation to light.