To jump through walls, you must have a cliff, ledge or something else high up that you can climb up to. When you are on top of the cliff/ledge etc, charge jump to the Kuzco door or any other closed door to fly through the wall. If you are too close to the edge of the cliff/ledge etc, you might fall of a cliff (if there are any) and lose a life. Sometimes, you might just his the wall and fll back to the ground or onto the door's frame. If you are placed in the right position, you will fly through the wall. This cheat works best for the Mountain -- Chapter 2 Bird door at the end.