I think the video was accelerated (look at cars in the background or wind in trees/on grass or the occasional bird/insect).
Which means the drone may not have been as fast/manœuvrerabke as it looks.
It would explain the crazy Camera tracking skills.
Definitely not accelerated, just ridiculous thrust to weight ratios on those mini quads. You can tell from the sound - the pitch corresponds to RPMs you would expect from those specs (which are listed in the description BTW)