Occam's Razor says that defying gravity should not need to be so complicated, and you can see it defying inertia if you watch it closely near the beginning and end and about 60-72 percent of the way in. What fascinates me is how complicated a movement, involving at least 3 bodies, is operating at the crux of this video.
Watch This Freaky Gyro Cube Balance Perfectly, Defying Gravity.