In addition to the fast-rising ass, here's a few other things I noticed:
-Try to extend more (i.e., "stand tall") -- it doesn't look like you're opening up your hips or extending your whole body much (see pic)
-Related to the above, be more aggressive with your 2nd pull...really push yourself off the floor and make that bar move fast!!
-Looks like you're looping/windmilling the bar out in front as well. Keep it as close to your body as possible. Might have seen some early arm bend as well, but was difficult to tell from the YouTube vid. Before you commence each lift, try shaking your arms out a bit and turning your elbows very slightly outward.