Game demos are typically a controlled experience, even if you're holding the controller. A public relations figure tells you where to go, what to do and points out features. It can take away from the experience of actually playing.
My hands-on experience with the upcoming first-person shooter "Legendary" from developer Spark Unlimited and publisher Gamecock, however, was the opposite. Someone handed me a controller and just watched me go.
Having been in many a game demo, I appreciated that.
After 20 minutes of hands-on time with mythological shooter later, my favorite "Legendary" moment was unleashing a mutated werewolf, who meant to tear me to pieces, and quietly forcing him to take out my foes.