You can see in the video that this muzzle break, rifle, ammo and shooter combo work too well. The muzzle actually dips after each shot.
Normally the rifle will recoil up and left for a right handed shooter. Both are a matter of kinesiology. The rifle recoils straight back (especially with an AR), and your body pivots at the hips and back bones making the rifle move up. The rifle is sitting on one shoulder and when pushed off center the body twists that direction. So you get the rifle recoiling up and right.
A muzzle breaks or compensator work by using the pressurized gasses that are pushing the bullet out of the barrel to do other work. The break will vent some of the gases up, pushing the barrel down. And it will push some of the gasses back toward the shooter pushing the rifle forward. So you feel the rifle recoil less.
With a 5.56mm it is not a big deal. When you get to .338, 3.75, .401, .50’s, and other really heavy calibers the muzzle break and compensator can make the gun’s recoil feel a lot less.
For extra credit: What is generally the best compensator style on the market?