Barry thankyou for posting, its a great little action sequence. Nice poses. I like it. There are a few things you could do to make this work better.
-It feels a touch CG or unreal in its movement and needs more natural weight and mass. For example, the beasts swing seems a little light. If there were more cushioning, wobble, follow through and settling, it would feel like there were more of a mass and weight to the character. He looks like a big fleshy beast to me and id want to get that into the character. After all hes missed the little guy and we really want to feel the weight of his arm pull the torso around as he tries to regain balance. His arm seems to move a little fast for its size. Look at fine tuning your motion curves to achieve this.
-Film yourself going to grab something and missing it and see what happens to your body. You might even find yourself stumbling forward. I noticed a step just after that swing and i think it might work better if it came a little earlier right on the end of the swing, as a stumble.
-Just a note about camera animation: Make sure that the camera follows the action and doesnt sinc with the action or precede it. The camera can add to, or take away from any animation depending on how it moves with it. Animate a camera as if you were holding it and following the action. Theres quite a lot of space at top of frame and i think you could bring the camera closer (tilting up to follow the action). It would make it more dramatic and readable when the little guy jumps behind.
-I love the fact that the little guy jumps out of sight and leaves the beast wondering where he went. And the angle of the jump and its roll feel really good. Again there is some tweaking to be done to the weight of the character. Its ok to do big jumps if the landing is suitably heavy.
-You mentioned the little guys energy, and i think its because we dont feel him being tossed around up on the head of the beast. I want to feel him hanging on with his weight being thrown from side to side. He might even lose footing and scramble to get back up. Offset his side to side movement from that of the beast.
-The slice around the beasts neck with the landing is a little too theatrical, convienient and light for me. I'd seperate the cut and the dismount, so we can read them individually and make both of them solid actions. When the little guy lands make it heavy and the we want to feel an anticipation and push off to the start of his run.
-When the beast grabs his neck and falls it could be more dramatic in posing with him flailing bacward rather than just slumping down, side on to camera.
Its a nice action sequence with some great posing. Well done.