Methods and apparatus provide for controlling an image display apparatus worn on a head of a user, including: producing a planar image representing virtual objects in a virtual world, wherein the planar image includes characteristics that require the image display apparatus to be a non-see-through image display apparatus that does not allow the user to visually recognize real world objects outside the virtual world; and displaying the planar image on the image display apparatus in a display mode that changes a shape of the planar image as a function of a change in position and/or orientation of the image display apparatus, wherein the change in the shape of the planar image includes presenting the planar image in an orientation other than a front direction of the user.