You look very noodle-like out of the bottom. Instead of leading with your chest, which is exactly what happened, assume more of a neutral spine angle. Also the manner in which you approach the bar, as well as the position at the bottom looks flimsy. Retract the scapulae, lock the lats in, look down, brace hard and tighten the abdominals. You're also over-pulling to some degree.
Once the angle at the hip reaches full extension, the lift is over, and any further translation/horizontal bar movement is not work against gravity and will not benefit you whatsoever. As for the position of the head, activating the cervical extensors via lifting the head does create tension along the upper back, but for the sake of establishing a neutral spine angle(the most efficient way for the vertebral column to bear a load) it is imperative that your cervical spine remain aligned with the neutral angles set from the lumbar and thoracic components of the vertebral column.
Other than that, practice, practice, practice. Introduce paused deadlifts, or even deficit pulling to strengthen your position out of the hole as well as through the rest of the range.