Yes I have seen it, many times, including the newly restored and digitally enhanced version.
We know the final shot came from the rear. This is indisputable for a number of reasons.
1. The only plausible sniper positions from the front either don't have the shot or would have had to shoot through the windshield. Clearly no bullet went through the windshield.
2. How a body moves when hit by a bullet is not nearly so simplistic as you make it out to be. How his head moves tells you nothing about where the shot came from.
3. Here in a America several different forensic recreations have been undertaken duplicating the conditions of that day as well as computer simulations. All demonstrated that all the shots came from the 6th floor of the Texas School Book Depository Building and duplicated the wounds (including the contentious head movement) with almost un-canny accuracy. Most of this is available on Youtube - some links below.
http://www.youtube.com/watch?v=9RCX3RdVHqo&feature=c4-overview&list=UU13g7Eg_atpU8htyE1LbCrA
http://www.youtube.com/watch?v=_RX2phbWmgA
http://www.youtube.com/watch?v=PfSXkfV_mhA&feature=c4-overview&list=UU13g7Eg_atpU8htyE1LbCrA
http://www.youtube.com/watch?v=DSBXW1-VGmM