The reason for the slice multifold. You lock your right hip on the backswing. You lay the club off during your backswing and then try to compensate at the top with a manipulation. You don't stay behind the ball on the downswing. Since your R hip and leg are locked, you have to shoot hard back toward the target, which makes it hard to stay back.
The reason you go from slices to hooks (inconsistency) is because your backswing is so flat. My God, man... Your plane borders on paralell to the ground. With a flat swingplane, timing must be exact for a staright ball. Hit the ball "early" and you either have a hook or a push. "late" and you have either a pull or a slice, all depending on clubface position.
I would work on kicking in the R knee a little at address to guard against locking that hip out. I would also work on a more upright plane, which will be on the target line longer, and thus requiring less perfect timing. Also, I would work on less manipulation to have the club square-to-slightly-open at the top of the swing. Lastly, I would quit trying so hard to keep my head "still" and over the ball so long after the club has cleared. That too leads to inconsistence. Let your shoulders naturally pull your head up towards the target. Besides consistency, this will also prolong your golfing career by not fracturing your back as you grow up into a man.
Besides that, looked perfect. Or, I could be wrong about all of it. JMO.