Looks pretty good i think the problem is that the reactions are so small... like when the marble hits his head its like he doesnt react to being hit (flinch away) hes just a little rigid. Also i think theres a shrug of the shoulders too which is almost un noticable. i would also expect longer reactions for example when he touches his head i would also expect him to 'rub it better'.

What you have so far is good made me chuckle good luck looks like fun.