Foot work looks good.  Timing looks pretty good.  Backswing may be a little late but should not be a problem.  Your backswing is fine.  It is not throwing off your swing.  Problem seems that you are forcing the shot from the high point through the follow through, causing you to grab and tug or push the shot to the right.   Relax your swing through the follow through and you should be a lot more consistent.  Let the ball and gravity do the work. 

Yes, Paddiwan.  Let the force flow through you.

Sorry I'm a bit late to this party.  I don't usually stray to far away from the Misc Non-Bowling forum.

You don't really drift left.  You actually take 2 pretty distinct steps to the left, particularly on your 4th step.  Your 2nd step also goes distinctly to the left.  The tendency to move left is probably due to your eye-dominance.  The "drift" is your natural attempt at keeping the target in a consistent line of sight.

Fixing the problem isn't terribly difficult - you just have to work on consciously stepping directly in front of your right foot with your left foot.   If you imagine your target 'pulling' you into itself, you'll get beyond that out-of-line approach and your targeting should improve nicely.