Looks good. Very focused. I personally am not a huge fan of shadowboxing, but I do it because I know it's beneficial. Otherwise, I find my mind gets lazy and I have to try hard to keep thinking and focusing on my goal and visualization. You on the other hand, look like you are focusing on an imaginary opponent, rather than just going through the motions.
Real heavy on the front foot. When you throw the left hooks/uppercuts, the weight stays on the front foot. It should transfer to the right foot. This sets up the right hand. Watch when you pivot- that is when it really stands out how heavy you are on the left foot.
Try to vary your tempo some more...mixing fast combos with slow ones. You seem to know punching mechanics, so I'm not sure if it's intentional or not, but you were arm-punching quite a bit too (hooks/uppercuts like the other poster has already mentioned).
