In addition to what he folks said above, see some improvement on the picking hand as well.
If you watch when you shift from the chords to the riff, you raise your picking hand elbow up. Your picking looks a bit more uncertain and uncontrolled. I normally keep my elbow pretty close to top of the guitar. Strumming movement is mostly at the elbow, with a small amount in the wrist to aid in pick angle - your strumming moves mostly at the elbow, but something looks off in the height of the elbow.
I tend to maintain my hand position so the heel is just over the bridge. Later you will learn about string muting and you’ll need to be there. This will mean dropping that shoulder and elbow down so a normal position will be with the heel of the hand over the bridge. It will ease tension on your shoulder and you won’t get neck/shoulder pains when practicing a long time. You will also find you are able to strum across the strings at a more consistent distance from the bridge.
Why is distance from the bridge interesting? experiment and see 
you will notice that you get a lot more high-pitch sounds from strings the closer you get to the bridge. The converse is true until you hit the half-way point (12th fret) where it sounds more like a harp due to less of the higher pitch elements.
Last thing I notice is the delicate pick grip. That pick is likely to spin in your grip and will probably want to use a bit more thumb and more of the side of the finger to hold it. See the lesson and chat for the pick grip here: How To Hold A Guitar Pick
The flexibility of the pick can help early on and you can plan to outgrow your beginner preference. Some discussion about picks here: Pick trouble