I watched it through once and it was okay. The plot isn't horrible, a bit confusing, but that is easily worked out.
Take the kings off first, set them aside. If you flip both over together lift 3 and show, put them down switching order...it'll accomplish the same thing a little smoother.
When you wave the kings, do it further away from the deck, shake both hands and let one go into the deck and then let the kings have a card. Bringing it together makes it seem fishy and will have spectators thinking of methods we could never do...though they will now think there is a method.
Clean up the ideas. When you say 'I learned this at hogwarts' don't just snap, say something like 'cardo reverso' (tongue in cheek, obviously) and then have the joker reversed.
You weren't set-up for ease of handling, if the table for the kings was on your right side it would have helped, the packet shouldn't come close to the deck, maybe put the deck down and pick up the kings or something.
Maybe start out by taking the kings out and then saying 'In just a moment I'll get your card to jump to these kings'. *card selected, do portal to show how you can have the card jump* then say that you'll do it again. *do first motion, nothing on other side* Look at the kings and pick them up, Joker.
Then go on.
This is what everyone else is saying, the creativity is good and the scripting works for your character, just clean it up and make everything 'flow' a little better.