One of the few examples where the special effects saves a mediocre movie. The story you've heard a thousand times. One-dimensional characters and dialogue. Predictable and boring in many places. There's also the common liberal theme of "Americans are evil" that runs through the entire film.
However, even with the cliched script, this movie is really, really good. And it's because of the special effects. They really do immerse you into the movie and draw your attention away from the weak script. You must see it in 3D or IMAX 3D, or you are wasting your time.
I would recommend this movie to just about anybody. It really is a phenomenol breakthrough in special effects. If it doesn't win the Oscar for that, it will be a tragedy.