I actually enjoyed watching this. It was sort of a typical story but it felt like a human reaction to everything that happened. When I saw Sam Rockwell I thought this might not be a role that he'd be good at. I saw him in other roles and he seemed to upbeat or funny for what he was supposed to portray but in this I found him convincing.
As the movie opens you get a bit of a back story to why he's there. When it cuts to him running on the treadmill you get the feeling he's used to what he's doing. His over grown hair and beard show he's not bothered to how he looks as no one else is there to look at him. His colour is quite pale showing signs of how long he's been there as well as all the stains and dust all over the base.
When it shows him going out onto the lunar surface I get the feeling that it's all miniature models. Reminds me of Star Wars. The grey tones everywhere showing nothing is around apart from him. Inside the buggy is white a reflection of being.
Inside he's recording videos constantly to log his progress. He's put faces for every day he's been there in the bathroom showing how he feels and all the pictures around the base as he constantly doesn't want to feel alone. He has life in him when a message from home comes through but during it you can see him have a longing urge to touch/be home as he listens to his wife. When you see the video cut you immediately feel like something is being hidden. This is wear you see him slowly lose himself. When you see the girl in the yellow dress you really feel lost. She's the focal point if the bright colour she's wearing and he subtle movements makes you watch her intensely.
He continues his work, chatting to Gerty, his only source of company. He sees something else, tries to brush it off while taking medication for a sore stomach he mentioned. As he ventures out again into the cold, grey lunar surface you see something in the distance and curiosity gets the better of Sam and he crashes. As you watch the inside buggy flash red you feel worried for him especially as the lunar dirt piles up on the windows.
Suddenly it's very bright, he has colour in his face and he looks almost like new in a way. As you watch him struggle to get up you pass it off, relating it to the accident. As Gerty is sitting talking to two men and as Sam blunders in Gerty covers up what he's doing. Here I felt Gerty might be keeping Sam from returning home.
Sam does Gerty's tests, getting agitated it suddenly goes back to Sam running his normal days. Sam seems different. More hot headed and less tired and used to what he's doing. Sabotaging the pipe makes everything yellow. The colour feels of danger and when Gerty suddenly turns the lights back on everything seems normal until Sam notices his usual suit is missing.
Venturing out again it's very grey and dull as usual and as he pulls up to the crashed buggy from before, see the light flickering inside you feel like he shouldn't check. Something is very wrong. When he discovers the body and brings it back you feel confused. Then he drops him, Sam yells at Gerty to tell him who it is. It clearly looks like Sam and Gerty confirms this. Gerty's face seems confused too but he knows. When the body wakes up you see it's Sam. The Same Sam that's drained looking. As the 'newer' Sam watches him wake up Sam feels confused, maybe feels delusional. Things become interesting when Same wakes up.
Newer Sam is colourful to continue his freshness. Sam is confused and upset. He's broken at what he's seen and it slowly develops in him being less and less well. He continues to degrade as he conflicts with the newer Sam. They fight, accuse each of being clones and after a bloody scuffle they bond a little. The lighting stays neutral and cold. Sam is dressed in drab colours while Newer Sam is still dressed in vibrant colours. It reflects how different the two of them are. This theme continues through the rest of the movie. As they discover the secrets of the base and the impending 'rescue mission' on it's way Newer Sam comes up with a plan to get back to earth. They find what's jamming the signal home and find the mass amount of clones underground. The way it's lit down there reflects the dead silence and sleeping clones. The light at the end of the tunnel maybe a symbol of when they wake up gradually one by one.
As the story draws to a close and you see them wake a third Sam for the plan home, Sam is drastically worse. He can barely move and as Newer Sam leaves him where he found him and sets up a harvester to help the next Sam contacting home you get a sense of acceptance of who he is. As you see the journey home and the Eliza crew finding Sam you want to know what happens. Gerty is reset for the new Sam and you want to know if he'll be the same. The closing scene with the ship entering earth's atmosphere and the radio/televison transmissions talking about Newer Sam giving evidence and you wonder will he expose what's going on or will it continue to run how it's always been?