I like that a lot, at the end the stickman appears to be a bit wobbly though. But you drew the stickman consistently, the standing up looks really natural as well. Great work!
It looks a bit shaky, but that's hard to avoid when animating slow movements in Flipanim. I think the movement of his arms near the end of the animation could've been done a bit earlier with some anticipation when he stands up so there's not much of a pause in the middle.
Overall, very nice anim !