Forget all that. Another Earth is a psychological drama in a similar vein to The Night Following by Morag Joss. A tragedy occurs that slings two strangers together into a dark and depressing world. The story of the second planet is ever-present, but in the background for the most part.
The story throws up some interesting questions, such as: What would you say if you met an identical version of yourself, with identical memories? ("Give me all your cash, or I'll grass you up for that unpleasant incident involving the vicar, a lorry full of marmite and the Swedish ladies rugby team.") Are there any differences between you and them? Have they made better choices? Would you even want to meet them? (At least, I'd be able to talk about films without being on the receiving end of a blank, slightly worried look.) The concept of a second Earth got so ingrained in my brain that I found myself expecting to see it in the sky as I drove home. All I really saw was a white rabbit. Not in the sky. On the road. I felt like I was in a David Lynch film.
The two leads Brit Marling and William Mapother (who supposedly worked for very little money) are both convincing and draw you into the story. To be truthful, Another Earth doesn't have the most gripping of starts, but due to the quality of the acting and script it lures you into its obscure little ways. The film finally becomes interesting when a discovery is made by SETI during an attempt at first contact. And anyway, any film where a fella tries to woo a lady by playing a saw can't be all bad. It sounds gorgeous, (probably best listened to in a cinema) as does the atmospheric music by Fall on Your Sword. For some saw action have a listen to the Saw Lady who actually played the piece in the film for William Mapother to mime over.
I saw Hugo the day before. It has a really butt-numbingly dull start and then gets a little bit better. This film is way better than that even though it follows a similar pattern of gradual improvement and was made for a fraction of the budget. (Four thirty thousandths to be precise. Ish.) Well worth seeing if you don't mind the lack of space marines blasting aliens into chicken nugget style chunks.
If you like this you could also try:
Monsters, Mulholland Drive, Starship Troopers (if you really want alien death).