Collapse Castle is an area of Omarine Zone visited by Kirby in Canvas Curse. Collapse Castle shares design elements with Rift Ruin, both appear to be the interior of a yellow brick building. Collapse Castle has companion stages in the Rainbow Run game mode. Three medals for Medal Swap purchases can be obtained in the main game, and six more can be in obtained in the Rainbow Run challenges.
Lanterns and dark rooms challenge Kirby in this area. The darkness hides several hazardous elements such as spiked walls, spiked shutters, rotating spiked arms, and electric tiles. One particularly nasty room has Blados chained to fans and very few lanterns. The medal for the area can be found in this room along the right side of the floor. After navigating several areas with spiked arms, a switch blocked by twin pillars of electrical rays will activate the spiked shutter to progress. The map of the area snakes from left to right throughout the entire stage. Waddle Dees are the only enemies present that can be defeated.
Area 2 uses pipes to connect rooms. Kirby is automatically pulled into the pipe when close to it. This area also uses blocks with arrows on them as puzzle devices. The blocks will move in the direction indicated by the arrow. These puzzle devices are used to access areas, limit Gordos movements, and block lasers in the static field that does not allow ink use. Colored switches positioned beneath lasers and corresponding shutters are used as another stage challenge. Kirby must activate all of the switches in order to progress. The final stretch of the area has a large anti-ink zone and switches that open the shutters above pits. Just on the right side of the exit door, a large blue Action Block can be seen blocking access to a bonus area.
This area reappears as the Line Trial challenge of Rainbow Run.
This area is another area focusing more on puzzles and challenges instead of combat. The first chamber is over a deadly pit and filled entirely with an anti-ink barrier. A series of rotating contact-activated cannons and fixed position cannons make up a new challenge. Firing in the wrong direction will cause Kirby to return to the first rotating cannon. The bumper pads and trampolines also serve to guide Kirby. No enemies appear in this section, but the medal can be acquired with proper timing from the only cannon on a Bomb Block as it falls.
The following area consists of a serpentine tunnel followed by a vertical shaft in which can simply be passed by riding a green pad. Waddle Dees, Bouncies, and Flame Shotzos are the only enemies present.