A great movie, I have always rated Sam Rockwell as a great actor and in this film he shows that. Like you mentioned, I give him credit because he's basically alone through the whole picture and he carries the whole weight of the film. Other aspect I thought was cool, is that you can tell that GERTY was a Hal-9000 inspired creation but I liked that, I saw it as a tribute to Kubrick more than a ripoff itself.
Loving your reviews man, keep it up!