There are two loading screens in Okami: The first one is a trail of paw prints followed by a picture of Issun, you can make the paw prints bigger by pressing X a little bit before they appear. The second is a screen where pressing X multiple times will place a number of paw prints on the screen. On particularly long loading sessions one can attain demon fangs. By carefully pressing X on the "trail" loading screen all the way through where you would normally see Issun, you will see big paw prints and a demon fang. The second type press X as fast as you can until you see a demon fang. Each time you do this correctly those demon fangs will be added to your inventory.