I like your head position after the first set, keep your chin tucked down like that.
Push your knees out further as you reach the bottom. A bit harder to do without shoes, but try your best.
You can hold the bar a little lower on your shoulders. Try to place your hands even more on top of the bar, and a little lower on your palm. Make sure you keep both wrists straight. It's hard to say from this angle but it looks like you sometimes forget about your left wrist.
Your back extension is a bit exaggerated on the way down, it's not necessary to be in that much extension. All that you need to do is keep your torso perfectly rigid (using a correct valsalva maneuver) in normal anatomical extension. With your torso held rigid, you should then think about dropping your hips down into the hole between your heels. And again, pushing your knees out here will help reduce your spinal movement at that point.