It could be a very interesting project to show your animation skills, unfortunately they all feel a bit rough. For example, the first pose you start with, has a broken wrist, the hips are not rotating allowing the right leg to be in a similar position that you have, right feels is bit too far back and the way the back foot angles it seems to be breaking his leg as well. Chest is not involved either with his action, there should be some rotation to allow his right arm be a bit further back than the left. The knee that is on the ground should be your contact point for the whole body, meaning that you wouldn't be able to slide it back and forth like that. Also, your front foot should be further back giving support to your body, think of them, as your pillars and to support the weight, this should be in the center.
I would suggest to shoot reference of yourself when possible. In this exercise, it should be possible for all of the actions. Once you are down filming it, feel your body, feel how the hips rotate in order to allow your movements, as well as the chest. Avoid the sliding of the feet around. When he gets up is completely off balance, he would not be able to get up like this.
Once again, shoot reference of really pay attention to how all the angles play an important part.
Technical things, hand is floating from the gun, he is not touching the concrete when leaning forward...