My campaign looks awkward on the player but looks good when I was making it.

You need to make sure that the screen resolution of the screen that you are using is the same as the campaign or this will happen.

Additional note: converting from a low quality image(640×480) and stretching it to a HD image(1920×1080) will just cause the image to stretch and pixelize. Be sure to use high quality images all the time so that no loss will occur if in case you need to shrink or enlarge it.