Go up the bridge directly ahead of you. At the top, wait for a Rolling Barrel to pass, then go to the crystal crate and stomp it open. Wait near the start of the bridge for another Barrel to pass, then run across and move to the side as soon as you reach the other end. You'll note that the Barrels follow the icy path. Repeat this crossing to the next island, stomp open the crystal crate there, then prepare to run up the longer bridge. If you start running as soon as Barrel passes, then the next will fly over top of you, missing you, as you run up the bridge.
Above, break open the crystal crate, then start up the bridge as soon as a Barrel passes you. Again, you'll duck underneath the next Barrel. At the top, follow the row of crystals, but wait for the falling Boulders to pass before entering the valley. Repeat for leaving the valley at the other end. Stomp on the crystal crate at the end of the icy path, then on the platform crate to the left. Go up the series of crumbling platforms behind the platform crate. Smash open the crystal and Platform Crates on the next landing, then follow the next series of crumbling platforms. Repeat this twice more, then follow the crystals until you enter a cave.
Out the other side, Barrels come rolling in from three directions. Go up the right bridge, immediately after a Barrel passes, and smash open the three crystal crates above. Keep following the bridges upward. Defeat the Devil Dantini, then hop across the crumbling platforms to an island with a lone crystal crate, stomp it, then return once the platforms regenerate. Take the other bridge down to the center island, go straight past the tree and up to the left side of this area. Defeat another Devil Dantini, then take the crumbling platforms here out to the Gold Key and a crystal crate, and back again. Before returning to the center, go down the other bridge to find the last three crystal crates, giving you a total of 100 crystals.
Return to the center island and move away from the point where the Barrels begin their run. Here you find the Cage containing the Jigsaw Piece. Unlock it with your Gold Key and collect it to complete your task.
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