"If you've not read the above review then be warned **SPOLIER** Personally, for a little while I was wondering whether the other Sam was a physical manifestation of the darker side of his character - maybe he was going crazy and talking to himself? Do we ever see GERTY directly address the second Sam before the 'revelation'? So the reviewer announcing exactly what he IS would have ruined the film for me. I loved Moon, it was nicely paced, beautifully shot and Sam Rockwell is one of the most underrated actors in Hollywood. Definitely worth seeing, although it may not be for action fans."