It's hard to tell, but from what I can see it's functioning normally. When you squeeze the bow the screw turns.
Are you certain the tensioner is seated in it's little pocket in the lower case? It has a lot of movement, possibly more than normal.
Also, I didn't see the little M6 bolts attaching the head to the jugs on the intake side, using those? Won't cause your problem but if you're leaving out bolts it could be hinting at other things not being up to snuff. Not knocking you, just trying to point out possible issues.
Drop the pan and look up by the crank. You should not see the tensioner end.
Read dave500's posts in this thread for proper tensioner location.
http://forums.sohc4.net/index.php?topic=113772.0There was a member recently that removed and I believe reinstalled the tensioner without raising the jugs as is normally required. I forget who and where the link is, but he said he made a little fixture or something. I can do a little searching if you need to remove the tensioner.
All that being said, when I've been putting cams in and the tensioner is relaxed against the chain, my cam chain is still tight. I wouldn't be able to rotate the cam back and forth like in your video. Maybe your chain is too stretched. I have heard of people using a heavy duty split chain so they don't have to split the cases. Could be an option for you.