No expert but this is from Rippetoe. Depending on how wide you are standing, you can lean forward SLIGHTLY. The reasoning for this is you will stretch your hamstring so it is easier to get out of the hole. I used to squat ATG but now I take a wide powerlifting stance and dip below parallel. At the bottom, hamstrings coiled and I drive out.
Also, another tip that worked wonders for me is the cue "spread the floor". Do this from the moment you plant your feet...try and "push" your feet away from each other. If you do it (you can try it without a bar to get the feeling), your outer hips should feel tight. If you do this coming out of the hole, you will engage your glutes alot more. Should feel really powerful coming out. The entire motion I repeat "spread the floor, knees out" in my head to cue myself.
Doesn't look like your knees buckle which is good. Only other thing is start the squat by pushing your hips back just a bit more like in the video sean posted.
These are just tips that helped me. It still looks like a solid squat!
