First off you will need a Gameshark Broadband Enabled for this. Activate the Walk Thru Walls code. Enable it during the game by pressing Select+R1. You will be able to walk on air and not fall and also walk through walls. NOTE

O NOT JUMP WHILE WALKING ON AIR OR ON LAND WITH THIS CODE ACTIVATED. YOU WILL FALL THROUGH WORLD AND NEVER BE ABLE TO RETURN!!! You will also walk through walls and do not deactivate this code on the first level while on land or air because you will fall through world and die. All other levels it will be ok to deactivate it. To enable deactivate walk thru walls, select the Walk Thru Walls Off code while in the gameshark The Mummy Returns code list and press Select+R2 to deactivate it. Still do not deactivate it while walking in air or on the first level. Cheers