King Kong y-axis problem

My brother recently got King Kong: the game, and we are having a small problem: It works fine, but the character always wants to look up for some reason. (unless you invert the axis, then he looks down). If you let go of the mouse, the view will point up at a constant speed as far as the view can go! This happened with the demo too (My dad works for a company that distributed it at one point). Is this a known bug/glitch or is it normal? (that would be a pretty dumb idea).

~Insectoid