Ex Machina (2014)

Just watched this movie the other day on Prime and really enjoyed it. However, the most painful thing about this movie is NOT knowing what happens after the end. Alex Garland says there won't be a sequel, but the whole ending so badly lends itself to be open to one.

It's almost like he wanted to inflict psychological and emotional pain on the viewer in a final sick twist. This movie messed with my mind. No wonder I loved it, what are your thoughts about it?