Some tremendous ideas here, as with everything written by Alex Garland. But the film is a complete mess, particularly the final third, which was almost comical at times. The CGI simply couldn't match up to the imagination of the writer - very little looked remotely real, and I found myself getting annoyed with it towards the end - desperate to finish the movie, simply to have the answers to my questions. I'd be staggered if any of the pseudo science is remotely possible, therefore it didn't seem believable. Anything with Natalie Portman in it is usually good - but not on this occasion. A miss.