Here are a few things to work on.
First, slow down when you're moving into the hang position. A big part of the problem is that the moment you start down, you're somewhat out of control. You take all this time at the top getting your air, setting your trunk and your balance... and then it's all suddenly gone when you jam the bar down to your knees at terminal velocity. Don't creep it down there necessarily, but make sure you're starting the lift from the proper position with the proper balance, or fixing the rest will just be an exercise in futility.
You immediately extend the hips from your starting position - but this starting position is too low/early to do that. The result is that you immediately push the bar forward with your thighs. Unless you're starting with the bar at the upper thigh, you need to initiate the movement with a push of the legs before kicking in with the hips.
The hip dominance continues to cause problems - First, your head is thrown really far back. Yes, I know Dimas did it, but he and the others who do it are exceptions. Generally this head motion/position cause the hips to come through the bar too much, and that's happening with you. That's also moving the bar forward and shifting your weight forward as you extend. Try keeping your head more in line w your back and punching up w the legs as you extend the hips - this will not only help get some more vertical acceleration on the bar, it will help prevent you from pushing your hips through the bar too much.
Along those same lines, the whole lift is very horizontally-oriented. You're essentially swinging your chest down, back and down again, swinging around the bar, rather than accelerating the bar up and accelerating yourself down. To fix this, punch the legs as described above, pull down slightly sooner, and focus on pulling down by bringing the elbows up and out as high and far as you can - force your body straight down in immediate proximity to the bar, but not by reaching for the bar with your chest. Remember that even if it's a power snatch and therefore a partial squat, it's still a squat - sit straight down with your chest up rather than doing a good morning.
After you pull and squat straight down, punch straight up under the bar. You largely just need to confine all this power to a more vertical channel. Explode up, pull down, push up, feet under the bar, bar over the base of the neck, chest up.
I would suggest a few things. First, do some hang snatches from higher on the thigh - a little above mid-thigh. From this point, you can immediately extend the hips and punch the legs together. Focus on balance, controlled movement to the hang position (and even a pause there), punching the legs up w the hips, pushing the bar in tight and pulling down w the elbows out/high, squatting straight down w chest up, and pushing straight up against the bar as you squat under it.
When you're doing that well, move your hang position down to above the knee - but now you need to start by pushing w the legs and keeping the shoulders over the bar. Legs only until upper thigh, then the leg and hip explosion together.
You may also want to take a break from power snatches for a while and focus on squatting under. When you can do that well, you'll be able to mimic the movement into a power position. You should be able to squat into any power snatch seamlessly - on your 200, you wouldn't have been able to do that because your position and balance were off from all the forward backward swinging movement.
If you feel weak pulling down, you can do tall snatches (but do them right, which may mean embarrassingly light weights).
All that being said, good job on the PR. Keep refining the movement and you'll be good for quite a bit more.