Samuel Wood’s review published on Letterboxd :
Scientific discoveries occur by accident and in the garage by white t-shirt-wearing mechanics. Primer's dull and ordinary setting and characters stress the film’s approach to science fiction—down-to-earth and believable. While this film is going for a down-to-earth feel, the plot is by no means straightforward and simple. Catching all the meticulousness details in the plot is quite difficult; re-watching this movie shortly after first viewing is highly recommended for those who actually want to understand what is going on, particularly towards the end of the movie.
As one might expect from a low-budget, indie film, this movie suffers from low production values, an unconvincing cast, and poor lighting and focus. Primer gives off an amateurish vibe, but for the most part these shortcomings are forgivable; one could even argue they actually emphasize how down-to-earth this sci-fi thriller really is.
With just a measly budget of $7,000, Shane Carruth has proven that mind-bending sci-fi can be done with just a little pocket change. Primer thrills, confuses, and simply blows one's mind. While not delivering everything a multi-million dollar budgeted film can deliver, this movie is sure to at least boggle the mind of any sci-fi enthusiast looking for a complicated plot to unravel.