The graphics and gameplay were enhanced and based on a better game engine than the one used in the first game, which allowed the characters and stages to appear less angular and more detailed. A popular and commonly discussed feature, one credited to Tomonobu Itagaki, was the level of graphical detail Tecmo put into the animated breasts of the female characters, as Tecmo went so far as to create a physics engine dedicated entirely to the animation of the female characters' breasts.