I like Matt Damon in almost every movie I've seen him in. This whole movie plays like the middle of a story. There's no initial plot or character development or effective "button up" at the end. I compare it (somewhat) to "Cast Away" with Tom Hanks. It seemed to most folks that I discussed "CA" with that Hanks' isolation on the island dominated too much of the film. In reality, his isolation on the island took up roughly only about 40% of the running time...the rest of the time was devoted to character and plot build up and wind down. That process was woefully missing in "The Martian". Additionally, the "rescue ship" in "The Martian" had a gym with too much equipment and a huge conference room, both with high ceilings and seemingly constructed with no concern for space or weight considerations. Didn't seem logical to me.

To me, numerous elements in the execution of the whole project just didn't ring true, even by a stretch, the last 20 minutes or so in particular. Don't want to create a spoiler here so I won't go into detail.

Unless it's a film by Clint Eastwood, usually when they make a movie like this or "Gravity" with Sandra Bullock, I kind of expect that they're not going to kill off the star. So it boils down to wondering throughout the film how they're going to keep the star alive and create a happy ending.

I gave it a 5 because I enjoy Matt Damon and the execution of some of the concepts relating to his survival, but in my view, the plot needed way more refinement and development.