Nice job, I like the little expressions which really add to it.
Just some things I'm seeing:
-The center of gravity looks off at the beginning, the feet are out in front of him
-The feet are extending down to the ground instead of the body coming forward to sort of fall into the step, if that makes sense, so it looks kind of robotic at the moment
-Walking up the stairs, the top half of the body looks a lot like a zombie... I usually look at the stairs as I'm about to go up
-Maybe too much arm swing
-Picking up the ball, I would anticipate the lift by having him lean back prior to the lift, rather than the back and the ball coming up together.
Keep up the good work, it's looking really fun.