Demos included feeding back the kick of a gun or the inertia and impact of a sword and flail (see: http://youtu.be/uD3hhIYr1f4 for explanation of the technology and the range of demos people were interacting with).
It's definitely something you need to feel to appreciate, but the expressions on people's faces go quite a ways to convey the level of engagement and realism portrayed in these demos... and this is just the start.
We're currently working on fishing, golf, and tennis demos.
All games were developed in Unity on a PC running Windows 7 and use a Razer Hydra for motion tracking.
Thanks to all who dropped by to try out our demo at GDC!!