Holy balls alive.
I'm a couple weeks late to the party, but I just tried Alone in the Rift demo...
http://www.neogaf.com/forum/showpost.php?p=62294189&postcount=2642
Probably the strongest showcase for why VR is next gen gaming to date.
Because even though the scenario is rote and typical, and it's just another typical girl popping up out of nowhere demo, and your brain expects it and all that...
The experience is so immediate, so visceral, so immersive, that your reactions will literally bypass your conscious brain.
You WILL scream in fear. I could see it coming a mile away. And the last scene before it cuts to black, one side of my brain was telling me to expect it, even as the other half was screaming out loud.
Was laughing at myself after that - certainly wasn't expecting to scream like a little girl!
Jesus. One of the most intense experiences I've had in any form of media. Just make sure you're standing while you experience this.