Sandra Bullock and George Clooney are nearly perfect as the astronauts whose ship is hit by space debris, leaving them suspended in space and desperate. The only other character in the movie is the Ed Harris' voice from Houston, but he's not even credited.
I'm not going to get into the story because if I tell you anything beyond the first five minutes, I could spoil it, but suffice to say that Clooney and Bullock are at their best--which is substantial. He's the old veteran, full of stories, an inveterate talker. She's the professional, the scientist with a task at hand. the chemistry is excellent between them.
I'm not much of a 3D fan--mostly because it's so often used badly and it's expensive (for me, the consumer). It is used well here, though it's still expensive. There are a couple of spots where it's quite good, as it was in "Avatar." Still, I think it's not necessary because 3D remains a gimmick, as far as I'm concerned, and this movie doesn't need gimmicks. The story's too good for that.