Two things that I noticed:
1) I am not totally sure because of the dark shirt and dark background but it looks like your back was rounded a bit during your first pull. It appears that your back and shoulders were not totally set before you began the pull.
2) Probably related to the first issue. You jerked the bar from the ground. Many folks will bend the arms slightly to get some slack and then jerk the bar off the ground. Your jerk was different in that you shrugged your shoulders slightly to get some slack before you jerked the bar. Watch closely and just before you pull you will see your hip angle decrease slightly, your hips begin to rise and your shoulders shrug slightly (thus giving you slack) before you pull/jerk the bar from the ground. Another sign that you are jerking it slightly is all of the racket the bar makes as you begin your first pull.
That is what I noticed. But you are snatching 170lbs very readily. So you are obviously doing many things right.
Hopefully sometime in the near future I will have a 170lbs snatch that you can critique.