It's not as bad as the reviews make out, I've seen far worse films which I've been unable to watch to the end with higher ratings.
Ok it is a little slow, especially the first 30mins and the CGI at the beginning isn't great. But it's got an interesting story, excellent acting and a good twist at the end which was totally unexpected but in a good way. Give it a go, sure it's not to Oblivion standards but it's definitely worth a watch.