[#54] - [w6l4p3]

Make your way to the large upper platform beneath the small platform with the enemy cannon, near #53. Place the ring right where the enemies land on this platform, then bounce off an enemy so that you're up on the cannon platform.

From here, let an enemy fall down, then jump - don't drop - onto his head. If you hold right, you should just make it onto the opposite high platform. Up here is a key. Grab it, then drop down and get the ring.

Repeat the process used in #53 to keep one of the enemies alive. Put the ring on the cannon to slow the fireballs. Once the enemy has made it past the platform they were being killed on, pick the ring back up and drop down to where the enemy has fallen. Follow closely behind him.

To the left is a cannon floating in midair. You need to bounce on the enemy from this ledge to reach it. Wait until the enemy drops to the floor, then run and jump on him. It may take several tries to get on top of the cannon; rewind if you screw up.

Now that you're on this cannon, place the ring as far right on top of it as you can. This will slow the fire rate enough that you can make it through the passage the fireballs are traveling through. So drop left, climb the ladder, and do so.

Open the door with the key you've been carrying around, and hit the switch. This will cause the platform behind the cannon shooting enemies into the death pit to rise, allowing you access to the puzzle piece.

Leave this spot by waiting until the next fireball comes through the passage, then run through, climb the ladder, and head left to get the puzzle piece.