Text-based explanation: On the floor where Prince Leo is held captive, toss the Sonic Spear so it sticks as low as possible, place two Bombs on top of each other, and time a jump so that the second bomb boosts you up to the spear. Then, keep climbing until you can loop around to the roof. (Since moonstones are important to the route, might as well grab the quick one at the center of this roof.) Lastly, stick the Sonic Spear into the upper right corner (more right than upper), and leap off the spear to get to the other side of the rift created by Katash's spaceship. There lies the Broken Blaster, which Thomas can repair for 10 moonstones after you learn the Royal Hymn from Leo. (This is how you obtain the Kobold Blaster before the Rocket Boots.)