Her face changes shape during movement, especially her nose, eyes and eyebrows. It's suddenly a different person in her last pose.
Secondary animation on the hair could be better, right now it doesn't feel very good. From the work part that comes after the animation i see that her hair is made with pegs? Don't use pegs for hair it looks very stiff.
Overall it feels like you are animating this straightforward which is why most of the problems I mentioned above are here.
Try drawing the key poses of your character and set them right. Make sure it stays consistent in all frames. Then add breakdowns which help you set the animation between your key poses. Than fill in the inbetweens.
This way your animation will have that disney smoothness I feel you tried to achieve here.