Overall: My first impression is that this is a soft rider.
Leg: Her leg has slid back and she has turned out her toe a bit too much, putting her in a weaker position without the support of her stirrup. The horse seems to be jumping to the right side of the fence (if the yellow stripe is the center of the fence), so she may be trying to push him left with the spur that is pressing into his side—she needs to be sure that is intentional.
Seat: Her hip angle is pretty good. I suggest she try jumping in a saddle without blocks because I think they inhibit a rider’s ability to stay with the horse in the air. That could be partly why her leg has slipped back—the block may be in her way.
Release: Her short release doesn’t interfere with the horse. I like that her hands are on the crest of the neck. Because the horse seems a little off to the right and she’s looking to go to the left, I think she’s using a bit of an opening left rein, which is good.
Upper body: Her back is relatively flat without being stiff and her eyes are looking to the next fence.
Horse: The horse has a cute expression. He looks a bit stiff with his front end.
Turnout: The turnout is pretty good. The horse’s coat and the braid job look great. The fit of the rider’s boots seem a little large. If they fit properly, it might help with the stability of her leg.
What you’ll see in the video: I’d like to see this rider a little more secure in the saddle, which she can do by working without stirrups. In the photo, it looks like she had a good release. In the video, she has more of a floaty release a little above the horse’s neck, and I’d like to see it more into the horse’s neck. But I like how she carries the hand above the withers and keeps a straight line all the way from her elbow to the horse’s mouth.
The faults they have going into the in-and-out are caused by a lack of straightness—the horse is pulling to the right the whole way down to the line, causing the distance to be a little different than the rider was planning. She’s having to keep the horse straight with her hand, which interferes with his jump. In a situation like this, the horse’s stiff front end comes out. He’s used to throwing his front end and jumping to the side to help get his front end out of the way. If the rider works on straightness, her horse will gain more athletic ability and might be better able to handle himself in that kind of situation.
One note about videos sent in—the best ones I’ve critiqued so far have been a little easier to see than this video. Parts of this one are far away, and a more professional video would be helpful to see better details.