Exploring the medieval-themed Castle MacFrights on Floor 6 of Luigi's Mansion 3 offers players a delightful blend of atmospheric exploration and tricky environmental puzzles. To achieve total completion, ghost hunters must track down six hidden collectible gemstones scattered across the corridors, armor rooms, and boss arenas. Mastering the unique layout of this subterranean stronghold requires creative utilization of both Luigi and his gooey clone to manipulate hidden mechanics.

Uncovering the Hallway and Armor Room Treasures

The first collectible jewel can be discovered early in your trek through the castle's main entryway. Use Luigi’s Suction Shot on the prominent suit of armor standing along the right wall to break it apart and reveal the hidden gem. This straightforward interaction introduces players to the environmental physics required for deeper puzzles ahead.

Further inside the castle chambers, the second jewel requires a bit more coordination near the grand staircase. Look closely at the tapestries hanging along the back wall and use your Poltergust G-00 to rip them down cleanly. Behind the fabric, a small alcove contains a mechanical switch that drops the prize directly onto the floor for easy collection.

Solving the Cage and Coliseum Puzzles

Reaching the deeper sub-levels reveals a complex puzzle involving a large hanging iron cage and a hidden floor mechanism. Send Gooigi through the metal bars to drop into the lower compartment while Luigi maintains control of the external ropes. Flashing your Strobulb on the green control panel will unlock the container and grant access to the third beautiful stone.

The fourth gem is cleverly concealed within the spectator stands surrounding the main jousting coliseum arena. After defeating King MacFrights, return to the upper seating arrangements and investigate the unusual structural banners. Pulling on a hidden loose chain using the plunger will open a compartment housing the hidden artifact.

Mastering the Cellar and Secret Vault Secrets

The fifth gemstone rests safely inside the damp cell block area, requiring flawless teamwork between your dual characters. Have Luigi pull the primary wall lever to lift the spike trap, allowing Gooigi to safely slip past the barrier. Once inside the isolated chamber, your green counterpart can use a burst of air to shatter the fragile wooden barrel holding the prize.

The final collectible requires a keen eye for invisible geometry near the castle's treasury exit. Shine your Dark-Light device thoroughly along the seemingly empty left wall corner to materialize a missing metal chest. Opening this restored container completes your regional collection and prepares you for the challenges waiting on higher hotel floors.