I am no expert, but in addition to what others have suggested, it seems to me that your knees cave in when you go heavy. This is no bueno for knee health. I'd make a modest change in stance and get your toes pointed out slightly more and concentrate on driving your knees out as you come out of the hole.
Also it appears that you are hyper extending your back. A neutral spine is preferable. As you set up, don't trade off a fully expanded belly for an over-arched spine. Really fill up your belly and press against the belt.
My prior coach used to say that the belly does the squatting, your legs are just along for the ride. I think there's some validity to this, as I think about my belly moving the weight I tend to get tighter, resist folding over in the hole, and resist hips rising faster than the bar.
Speed on the descent is an issue for me as well. I have difficulty staying tight if I drop too fast, so I'll err on the side of caution and slow my descent to maintain tension then try to pop it out of the hole with a bit of an accelerated descent in the last several inches.