I saw this today with 2 friends. One friend really enjoyed it, I thought it was ok and my other friend hated it (though to be fair she's not really into sci-fi and only went for our benefit).
I'm a bit of a harsh critic when it comes to recent films (not sure why) so take my opinion with a bit of salt but I was more disappointed that anything. I love time travel films but found the whole concept of this pretty stupid. The idea that time travel would be invented and then only used by gangsters to get rid of people they don't like isn't very logical. Also I do like films to give a bit of background about the future they present and that was clearly lacking.
I thought that the story was nicely 'wrapped' up in the end in a way that I wasn't expecting but that the middle part of the film dragged quite a bit. I was expecting a fair amount of action and futuristic sci-fi stuff but the film spends a long time in a very non futuristic farm house. I'm not adverse to a degree of character building and slow story telling, and the pay off was good, but I felt that it didn't blend very well with the rest of the film.
The film indulges itself in age old cinema cliches such as 'bad guys can't shot' and isn't ashamed to use the usual plot devices. By and large it does it quite well but it's not one that's going to stay with me.