World 8-Castle

 is the sixth level and first castle level of World 8 in New Super Mario Bros. It becomes accessible after completing World 8-4.

Layout
This is the penultimate castle level in the game, and features moving platforms on pairs of tracks. The platforms can change positions on the tracks by pressing switches that control them, similar to the ON/OFF Switches from Super Mario World.

The level begins with a set of these tracks. Pressing the switch will make the platform on them switch places, a technique that will be needed in order to progress through the level. There are also Dry Bones and Lava Bubbles present within the level, meant to impede the player's progress. After a series of tracks and switches, there will be a swinging rope that the player must use in order to reach the level's midway point.

After the midway point, the tracks are replaced with rotating platforms, in either triangular or rectangular shapes. The triangular platforms will keep their shape constant after rotating, while the rectangular platforms alternate between tall and wide after rotating. After a set of these rotating platforms, the player will come across another swinging rope, which must be used to reach the boss door.

Beyond the boss door awaits Dry Bowser. He is immune to all attacks (excluding Shell Mario's dash attack, along with the Super Star and Mega Mushroom), but can still be easily defeated by pressing the switch behind him. Defeating Dry Bowser will cause a bridge to spawn outside of the castle, making the second half of World 8 accessible.

Star Coins

 * Star Coin 1: Near the beginning of the level; after the second set of tracks, a switch can be found. The player must press it and ride on top of the platform on the top track of the second set in order to reach the coin.
 * Star Coin 2: At the fourth set of tracks; the player must press the switch so that the platform is on the topmost track, and ride on top of it. The platform will drop down onto another track with the coin above it, though it is guarded by a Lava Bubble.
 * Star Coin 3: At the end of the level; one last track is found underneath the platform with the boss door. In order to get the platform to spawn on the track, the player must ride the platform on the bottom track of the fifth set. After getting onto the track under the boss door, the player must duck to get under a low wall, then jump across a set of rotating rectangular platforms; the coin is hidden above a rectangular platform concealed mostly by lava.

Trivia

 * This is the only castle level that uses a different background than the original.
 * This is not the final level as when Mario or Luigi beat the level, Peach is not rescued yet.