A few things hit me right off;
First, is that it can be difficult to make a convincing walk with so few frames.
Second, is that your boar changes colors from frame to frame. The first is slightly darker than the second.
Third, he is moving each sides' legs in the same direction. Quadrapeds, or however it is spelled, move the front left and back right in nearly the same motion. Ditto with the front right and back left. I looked up a video to be certain with the boar.
Last, it is looking pillow-shaded. You will want to define your light source, and shade accordingly.

I decided I would do a quick edit just to help you out a little. When I opened up the frames I also noticed a few colors that could be considered extra, as the difference between them was not even noticeable. I made a few quick changes based on the statements above. Removed some colors, added 2 frames, changed his legs, and gave him a little bounce to his step.



I pretty much left the shading alone, and the legs are blocky because as I said, this was just something quick to help you along. Hope it helps.