From this point on the films becomes a psychological science fiction thriller. Sam realizes he is not alone. There is someone else on the base- and the identity of this person will change the course of Sam's life. That's all I will say. If you have seen the trailer you know who the other person is, but you don't know "why" he is. Neither did I until just before the big reveal. I love it when a movie can still surprise me. Moon is not a horror film, but it does have some creepy elements to it. Sam is isolated, alone, fearing for his sanity, and becoming aware that great forces are at work against him. Highly recommended.
The other Rockwell film I saw was Choke, based on the novel by Chuck Palahniuk. It is a really funny movie which stays pretty close to the book.
I also watched The Pregnancy Pact on the Lifetime channel last night, only because I was too lazy to get up and go to bed. The acting was on par with Death Tunnel. I have only myself to blame....(this film did not star Sam Rockwell.)