One thing I noticed is that your shoulders and elbows tend to get pretty tense...sometimes you catch your horse in the mouth over the jumps (sometimes your hands go down rather then up), and your hands go up and down with you as you post. You want your hands to be steady, right over your horse's neck, as you post. Try some no-hands exercises...either tie your reins in a knot and hold your hands out to the sides (or some other position not on the reins!) or grab them with your thumbs on top and all your fingers closed around the reins like a fist, and hold your hands really wide as you go over the jump. This helps you balance over your feet, without having to let go of the reins. Also just think about keeping your elbows at your sides, soft and following, and when you ask to slow down, think about pressing your elbows back into a wall behind you instead of locking your whole arm.
Also, your toes were pointed pretty far out sometimes, and your knees looked braced...think about using more the side of your calf and not the back, and point your toes forward rather then out. That will help with your knees, too. A couple of longe lessons wouldn't hurt to loosen you up! :)
Other then that, though, you really looked good...You have a very secure lower leg, something I am working really hard to achieve! You were obviously focused...your heels were down and your eyes up, and you weren't getting left behind or trying to jump for your horse. Keep working...just don't let yourself focus so much that you get stiff! :)