He no longer looks like a rectangle.

You're getting better. What you have now might be able to be used in a game, but I suggest you keep on developing your spriting abilities. Your animation doesn't look quite right (his legs look like they are compressing unrealistically), but I think that improving your abilities would be the best way to improve that. You have the basics of animation down (somewhat), and you successfully made a .gif.
One thing that might help you, especially if you have any talents with drawing on paper, would be to use graph paper. You can draw a normal drawing on graph paper, and then fit it into the grid, effectively creating an outline for a sprite. This was one of the methods I used when I was learning to sprite. Eventually I learned how to directly take what I imagined and make a sprite with it.
Another thing that helped me learn to sprite was mimicry, which in my case targeted Pokémon sprites. It's not something that should be used in a game, but splicing, recoloring, and reconstructing then gave me the ability to recreate the techniques I used with my original artwork. So I think that, for now, it's permissible for you to experiment with other people's artwork, in preparation for making your own from scratch to use in your games.