This was an excellent movie - so why did I only give it four stars? Well, as a critical move-watcher of films by Ridley Scott and others, I feel like there is a certain standard they need to live up to. I simply needed more from this movie.It is not bad, really, in any way, but it has some small flaws in it that are hard for me to look past. They might spoil the story for those that have not watched it, so I will not list them here, but they are significant enough to ding the movie one star in my mind.As far as the good stuff? Wow - amazing effects, and some stellar acting by Michael Fassbender. Really a great example of how detail oriented Ridley Scott is when designing a movie, which makes me feel a little more strongly about the flaws.In any case, if you are a sci-fi fan of hardcore science fiction, or a fan of the Alien / Aliens movies, this one is definitely worth the watch!