I knew that the main characters were: a female humanoid robot and (presumably) its bearded creator who liked to dance in red lighted areas. And from the movie reviews, I knew that there was something about the final scene. (And, for reasons that I won't explain, I thought that final scene involved the red lighted dancing and that the bearded dude was dancing with the robot mentioned above.)
So, I thought going into the film that there was some sort of twist ending and that the relationship between the creator and the machine was REVEALED in some dynamic way at the end. (I was purposely avoiding spoilers for a lot of this, so if you have already seen the movie, maybe you can forgive the mistakes that I have already outlined.)
It turns out that I was sort of right in these assumptions and completely wrong in many others. The dance scene--while cool--was not at all a pivotal moment at the end of the movie. And there was a complete THIRD character that I didn't even know about in the plot. (Well, now that I think about it a bit, I guess there were a total of 3 and three-quarters characters in the plot. And I only count that fourth person as less than one because that character has very minimal dialogue and isn't in every scene.)
My misunderstandings aside, the goal of the movie is to get you to consider the nature of humanity and individualism and truth and power and self-identity. These are often the themes of robot movies.This one does add additional tension that is most often felt in a thriller--a new wrinkle that I did like.
A few extra things that I will say. The photography and visual design of the movie was really, really strong. The house that the movie takes place in is wonderful and mostly real (note that there are probably spoilers in the linked article) and I'd love to spend time there. And Ava (the robot protagonist . . . or is it antagonist, hmmm?) has a great design that emphasizes her mechanicalness strongly while allowing for humanity as well.
All in all, I recommend the movie. It has a sort of indie feel that reminded me of Primer, though the subject matter is very different and ex machina is much more understandable, and truthfully the visual quality of ex machina is better than Primer. But they are both small, intimate, focused movies on scientific conundrums . . . but they never lose the humanity that gets trapped within the science. You know what I mean?
See it! (Most likely only available as Video On Demand at this point.)