You are overextending your spine at the top. Stay more neutral and just get really tight when you take your breath. You want your torso to be immobile. Avoid the tendency to lift your chest half way up. Drive with your hips all the way to the top. I suspect your stance is a little too wide, but it is tough to say for sure. Get yourself some weightlifting shoes. You will be happy you did.
You're somewhat leading with the Chest... checkout 0:45 seconds into the 2nd vid you posted. (Senior Members, can you verify if I'm wrong on this?)
Also, I noticed that your head moves significantly. Probably, your eyes catches your reflection in the mirror; hence, you end up looking at yourself. You might want to do something about it since it'll affect your hip drive. (and probably why your chest appears to lead at times)