I just finished watching the Martian and I gotta say: the movie was fiction.
First off they want us to believe that Matt Damon and a camera crew flew to Mars — on a 414-day journey to film a movie for however many weeks/months it took to film and then flew back? Get real! It would cost way too much to fly to Mars just to film a movie. Not to mention all of the things that could go wrong (see The Martian for some examples). Most likely, they filmed the Mars scenes from the moon and they just colored the surface to look like Mars. Just like Hollywood can colorize old black and white movies.
So keeping in mind that it wasn’t real, the movie was still fun to watch. The cast was full of recognizable people and pretty much all people I enjoy seeing on the big screen.