So apparently, Jim's brain is now an actual peanut (this is according to the sketch currently on the gamesas homepage). As you may know, Jim in the past (in the tv show and in EWJ 3D) has had four brains (or at least four sections).
Maybe the fact that his brain is now a peanut is a part of the story for the new game. Sure, there's hardly any reason behind it, but it's a theory nonetheless.