yo, your footwork was good but stance could need work. ur back foot is to close to the front one, try to keep them shoulder wide and ur balance will be WAY better
No slapping is actually a reall good punching technique if you have correct technique. Slapping can make ur hooks faster an more snappier jus practice them
Only real difference I can see is he drops the jab down low as he brings it back then raises it up to guard. In the "correct" version he bring it straight back. He might give a tiny little hip pop in the "correct" version versus the incorrect which is more "deflated". Not certain. All the other explanations people give arent true if you just look. He leans in both. He turns hand down in both. He snaps the punch in both
Well extending your head and shoulders is a dangerpus move, but if they dont hit u when u extend ur neck in a jab and u hit then that jab will be more powerful, staying back is a good way to keep a distance