it's still good netiquette to state the sources, David might have very well walked away with the idea he was responsible for the character design as well.
the anim is a good first foray into animation, I think the precise pixelwork in the stepping motion is very well done and gives a good sense of all the motions involved in walking.
my 2 cents to improve the animation would be to add something like a 1-pixel wide and 1-frame long switch to his hips to make it feel more alive, specially on the background leg that seems so static as of now, I agree with all of the previous suggestions as well.
