This is another anatomical rendering by Jason Freeney of Sackboy's innards. As you can see, there are guts under that zipper. Of course, I already knew that because I got all stabby on him once when he wouldn't give me his wallet. Yeah, and all the king's horses and all the king's men couldn't stitch Sackboy together again. So, let that be a lesson to the rest of you.
Jason Freeney's Website
The Anatomy Of A Sackboy [kotaku]
Thanks to Julian, who
took one for the team and pointed out Sackboy's genitalia was modeled after his own so I wouldn't have to.