Its cool as a POC but i don't see that its an improvement over a std bike.
Regardless it looks like it would be a lot for this thing to turn that long tire/tube with just pedal effort. you'd always need a rolling start. Also if the speed was too great and your legs couldn't keep up with the fixie pedals, the sprocket teeth would just jump off of that flexible tire/tube which is also expanding & contracting and generally just flexing with the road, heat, etc.