I finally caught this on DVD. (I don't get out that much. A trip to the video store is a big event around my house.)
I had heard that the movie is great up until the ending, which I heard described as confusing and pointless. I can understand the confusion, because the movie fakes you out. It's pretending to be a certain kind of film that you've seen a million times. The kind that only flirts with existential dread. When Tommy Lee Jones showed up early on, I actually said to my wife, "Oh, it's Tommy Lee Jones, everything's going to be all right now". Which is exactly what I was supposed to think.
Like the motorist pulled over by the police cruiser in an early scene, you respond automatically to certain signals that reassure you that a safety net is in place. But the safety net hasn't held, and the tent around you is on fire. The film leaves you standing, slack-jawed and dull-eyed like cattle, watching the bolt aimed at your brain but failing to understand its purpose until it's too late.