Matt Damon has officially joined Tom Hanks and Will Smith as actors that can completely carry a movie by themselves. Literally. Just them on screen with scenery for the vast majority of the movie. There was a huge cast in this and there were plenty of scenes where they were back on earth at Nasa with all of them. But what really carried this movie were the parts where Matt Damon was all alone and trying to stay alive while awaiting his possible rescue. Damon did an amazing job of portraying the desperation but also keeping it humorously light at times as well. The ending of the movie got a little bit too fluffy and feel goodish for something that was so smart throughout the movie, but that really is the only knock that I can make against it.
I would definitely recommend people checking this out. It's a great movie both visually and acting/writing wise. They manage to make a very sci-fi movie a big time mainstream hit.