looks like a pretty typical fight between a trained guy and an untrained guy to me.
My deconstruction:
The guy on the left tries to come in, and the wing chun guy stop-kicks him and gives him one hit as the kick pushes him back.
Guy comes in again with a wild overhand right, and the wing chun looks like he tries to do pak sau block, but he's using the wrong hand for that if so, which might make it understandable why he loses his stance/composure, stiffening up while jerking his head back--this is a pretty standard reaction from someone who's been training, but is hit with a situation outside the scope of the training. He might have been better served with a tan sau or bong sau block. But such is life.
As the haymakyer goes past, the wing chun guy falls back into training and chain punches the dude's head.
The guy bends over and turns his head away while scooting in and hitting the wing chun guy in the ribs with a few untrained looking lefts. When he's scooted in close enough, he grabs the guys waist and picks him up. So far, this guy is doing things exactly what I would expect an untrained fighter to do.
As he's picked up the wing chun guy starts elbowing the other guy's face. The guy drops him and the wing chun guy does a basic takedown and chain punches him a couple of times until the guy rolls over.
It looks like really standard wing chun versus a 'street scrapper' to me.
I saw:
A crowd of white 'gangsters' 'throwing down' before the fight, lookin' all tough and stereotypical.
Then the Wing Chun guy makes a show of taking off his jacket and passing it to someone to hold (wtf?). Meanwhile, there's no increase in crowd activity in anticipation of the fight. Everyone is still making generic fight support motions in the background. Opponent is standing flat footed, but cracks his neck with his hands hanging loosely by his side.
Opponent waits for guy to assume stance, than lumbers in, only to be greeted by a front kick which sets him back a bit. He does make a grab for the leg but misses. (This may be the most realistic part of the fight). Once again, crowd is making stereotypical fight support actions, throwing air punches, cheering. They haven't much changed this behavior since the beginning of the video. Background characters in Street Fighter 2 were more realistic.
Opponent recovers and throws a very slow Hollywood haymaker that would have missed even if it wasn't blocked. but apparently the force of the punch was so much he bent over in front of Wing Chun. Still no change in crowd behavior despite the 'beginning' of the 'fight'.
A couple quick punches to the head of the opponent which could be connecting, or not. Hard to tell. Apparently they don't affect him because he opens his hands up wide like a wrestler and then closes them around the guys waist and lifts him straight up in the air. A couple quick punches to the head of the opponent again while being twirled in the air like a ballerina. Wing Chun is dropped, trips the opponent. Throws some more punches that may or may not be connecting and gives him a quick kick.
Crowd guy in the foreground throws his hat at the ground once the the throw is completed. And then kicks the opponent in the leg while he's down.
Meanwhile, magically they have stayed in camera and in focus the entire time.
All we're missing is "FINISH HIM" appearing over the screen.