The video has been sped up considerably. You can tell by the last technique, which kicks the leg to trip the person. That person should be falling purely from gravity and gravity doesn’t pull you down that quickly.
You don’t want to move your hand that far off the center when parrying a punch. That type of fist chasing slaps is usually discouraged pretty early on in most styles as it makes you easy target for faints as it opens you up. Also the “attacker” is too far away to even land that punch, which means she has more time to see the attack coming.
When she is launching her attacker her shoulders are behind her center of gravity(dantian) which means she would get off balanced if she actually landed the attack. Essentially there wouldn’t have been much power there even if you got hit.
The last kick that off balances only works because the attacker turn away from her after the failed push kick, which an attacker has no reason to do that. It would have been more reasonable and expected for the attacker to pivot on the front foot(taking the rear foot clockwise away from the girl) to face the girl again, which means the kick that the girl would have done nothing if things moved logically.