I've run one of those things a few times. . . You can get the basic movements down in a half hour, but you'll spend a lot longer time gaining that kind of skill. (I never got it. LOL, it was all I could do to not dig myself over sideways in it).
This guy clearly has a mastery of that unit, the mud field was moving as he tried to scoop. . . . knowing where the ground was going to move to, where his bucket had to be in relation to it to not cut the deer in half. . . . BRAVO.
Nice work from someone who's put in some time behind the sticks of one of those things.