Someone forgot Newton's 1st Law of Motion, and it's evident in all these videos. In other words: It's impossible to steer a device like this .
The thing works on repulsive eddy forces that always oppose the field you create. If you angle the field, you should get lateral forces.
edit - thinking about it, you do not have to angle the field, you just need to move it. Also, if you move the device it should automatically resist the motion due to the currents created. With some accelerometers feeding back into controlling the motion of the field, it should be even be possible to give the device what feel like edges to make it behave like a snowboard.