The hips and knees need to break at the same time. See your toes come up on a couple of these as you start? You're sending your ass back to start and the knees are delayed. At the same time, you still need to reach back more with the hips as you approach the bottom. Get your nipples between your knees and get your junk behind your heels.
Lastly, keep driving your hips. Emphasize the hip drive out of the bottom and don't be tempted to lift the chest so soon.