Jack is pretty likable character. The fact that he's so pure and lovable and loving and innocent to the point where it can almost be annoying I think is a good thing, especially since he's so desperately attracted to you and you only see this side of him, when he seems to have a whole different psycho side to him that is fueled by this childlike admiration for you.
I am curious, though... as this is a demo, does that mean you're currently working on a full version?