Why play when you can just watch?!
Beyond: Two Souls is getting a demo on October 1, 2013. Some people can get it right now though if you know where to look. Like on GameStop's Facebook page.
For everyone else, the entire demo has been uploaded to YouTube. And you know what? That's fine by me in this case. I have never been able to get into a David Cage game before. So I'd much rather watch someone else play.