Old one looked like a piglet.
I never liked the sprite for the boars. I reworked them. I think these guys look better. Also, I made the tusks a separate layer and as the boars level-up they get bigger tusks.
I realize that I don't really know what a boar's shoulder muscles look like and I kind of based these off human deltoids. It looks OK from the side but from head-on, it kind of looks like one of those perverts who's into dressing up as animals.
New one like a warthog. Its sprite is overall nicer and makes for a good enemy, but a boar should have a thick fur and smaller head.
I believe you're right about the shape of the back muscles.