Seems like Google copied this idea: http://www.refugio3d.net I actually built something similar myself in December 2013 for iPhone, using just some cardboard and a couple of magnifiers I bought in a book shop the same day. It works surprisingly well, and I was really proud of myself. ... Afterwards I discovered Refugio, and I realized it wasn't a new idea at all. Now it is Google's idea.
Also, from the same lab (MxR at USC's ICT) where Oculus originated [1]: http://projects.ict.usc.edu/mxr/diy/fov2go/ [1] "Spun out of MxR’s VR2GO and HMD prototypes, the Oculus Rift is the single most anticipated piece of VR technology to date." http://projects.ict.usc.edu/mxr/diy/
In any case, not really fair if Google gets full credit for this.
If anybody is wondering about the 3D. I build a simple stereo-image OpenGL landscape app, and used the gyroscope of the iPhone 5 to determine view direction.
It is actually really simple, and the lag really isn't that bad.
The biggest problem is that you can't really do anything without a controller.