Sam Rockwell is fantastic in this movie playing multiple versions of his character who are slowly losing sanity and will to live after discovering terrible facts about his existence. I really wanna say what those facts are because it will make this review much easier to understand but I can't spoil it. It really is a shocker what goes down with his character in the movie and Rockwell is amazing in the role. He practically carries the weight of the film and he does it incredibly well. He should get nominated for an Oscar.
One thing I didn't like about Moon was that it took a bit too long to build up to the big reveal of the movie. So for a good 45 minutes I'm left thinking what on earth is going on and slightly bored. But damn, when it get's there it just blows you out of your seat.