Oh,no, the Halberd!
Hit the Switch and ride the platform up. Press another Switch and inhale the Bubblehead. Enter the door. You can turn the Waddle Doo and many Parasols from the Shotzos into bubble items and collect them. For now, jump across the gaps before the Shotzos slide up. Wait for Foley to explode, then slide on the Star Blocks. Climb up the ladder, and leap over the Shotzo and break the Big Star Block. Go through the door.
Go under the crevice to pick up a Cutter Bubble. Keep dashing, and jumping over the gaps and landing onto the platforms above the Heavy Knights. Your upgraded Cutter ability can tear right through the enemies, even the Heavy Knights, making this part a breeze. Press the switch and enter the door.
When you first come in you'll notice Gordo coming your direction. Slide into the lower area and duck while he passes by. Then go down the ladder into the barrel. Stay in there until the Gordo passes. Press A and go left. Slide down the ladder, but be careful for the Gordo. Go to the right, and you'll see a barrel then a wall with Gordoes on the other side. Break the Bomb Block then quickly huddle into the barrel while they pass you. Jump out, take the platform down, and enter the door.
You will be put into a controllable cannon, and can press A to launch anywhere. The rooms are up-left, up, up-right, left, right, down-left, down, and down-right.
Up-Left: Inhale the fire enemy. Get down and tap on the control pad twice to burn left. Inside the barrel contains a Invulnerability Candy. Escape by going out the other way.
Up: You probably still have Fire from the previous room, but if not, go and inhale the Fire Bubble to your left. Float right and burn the candle to light the room. It is revealed that Treasure Chest #1 is below. To destroy the blocks, use the "Fireball" attack over them (tap on the control pad twice). Take the chest and leave.
Up-Right: Tedhaun sub-boss battle. He is a strong sub-boss, and the room is small with Gordoes above you. The best thing to do is to keep leaping up and using your Fireball technique on him. If you've been tossed around a lot, it's time to use your ability while using the previously-seen Invulnerability Candy in a bubble. After hitting him a few times inhale him for the Ghost ability. Use it to float up. However, across the flames is the second 1/3 of Life. First make sure your Copy Palette isn't full, then dash over with B, then dash your way out. Exit.
Left: There are three Copy Ability Bubbles in this room. You will need them for various tasks later on, so empty your Palette and grab them. The barrel below contains 1/3 of Life. Combine them for more space. Go through the door.
Right: There are various things in this room... use your Animal Bubble to cut the ropes. Be careful, as it is easy to die in this room. DO NOT cut the rope to the far right, or to the left. Cut the rope to the right and the rope to the far left, for a 1/3 of Life Bubble and a Maxim Tomato. Combine the 1/3 of Life for a 1UP. Exit.
Down-Left: If your palette is full, dump any unnecessary items out right now (except for the abilities we got in the Left room). If you get rid of everything except for the three abilities, you will have two slots available, which is all you need right now. Snag the Wheel Bubble, but beware: as soon as you take the Bubble, flames will shoot up. Use the ability to go right. The block will make you come to a stop, but hop over it and use the ability. Go quickly over the collapsing blocks to take Treasure Chest #2. Jump over the gaps carefully, so not to come to a stop as the world behind you explodes. Do not jump, however, at the end. Grab your Warp Star, get ready to leave this place.
Here you will quickly see Treasure Chest #3, just sitting there in plain sight. Spinni will come and take it as soon as you enter, however, so get ready to use those copy abilities.
Important note: Do NOT use Wheel here. If you do, you will instantly fall into the pit, and when you come back to life, the treasure, Spinni, and everything else will be gone. An ability like Ice is recommended. Keep freezing Spinni, but be careful that you don't make her fall into a pit with the treasure in tow, or defeat her mid-air so that it drops into oblivion. If you think that you aren't quick enough then wait for her to go to her den and fight her then, if you have ice or fire or spark then get her to a corner and hold B. Float to the Exit Door with the chest.
Note about the Down and Down-Right rooms: The Down room is actually useless, but the Down-Right room is basically the same as the Down-Left room: a way to get the third Treasure Chest.