Shane Caruth wrote, directed and acted in his debut movie Primer, which is quite an intriguing film. Upstream Color is his second movie, nine years later, which he again wrote, directed and stars in.
The first hour or so the movie goes down various tracks whilst nothing is obvious, nothing is explained, and not a lot is clear as to what is going on and why. This initially makes for an interesting and somewhat suspenseful enigma: it keeps you trying to figure out how things connect and where this might lead.