World 1-Castle (New Super Mario Bros.)

 is the last level and the castle of World 1, and subsequently, of New Super Mario Bros.. The boss here is Bowser.

Layout
The majority of the level consists of walking on tightropes over lava. Along the way, Mario encounters Podoboos and Dry Bones. There are also several platforms that move up and down, some of which sink into the lava. Eventually, Mario comes to safe ground. However, it is below a ceiling of spikes that slowly lower themselves down to the ground. Mario must jump to in-between gaps before he is crushed (one that has a Star Coin that Mario can Wall Jump to, and then get through a second lava-filled area (another Star Coin is on a moving platform that sinks into lava). Before making it to the boss door, Mario can jump on the last tightrope to find a hidden pipe with a Star Coin in another room.

Bowser is the boss of the first world. As Bowser Jr. original did not find a proper boss to inhabit this castle, he got his dad to do it. The fight is very similar to the ones from Super Mario Bros.; the fight takes place on a small bridge above a pit of lava, with a Skull Switch (replacing the former ax) at one end. Mario must get either under or over the Koopa King and hit the switch, which will collapse the bridge. After the Koopa King's defeat, he is reduced to a skeleton (Dry Bowser), and is not seen again until World 8.

Star Coins

 * Star Coin 1 - The first Star Coin is placed near the ceiling. Mario or Luigi will need to Wall Jump off the spiked ceiling crushers to get it.
 * Star Coin 2 - Near the end of the level are two platforms. One of the platforms has the coin, but the bros. will need to wait for the second platform to come up to obtain the coin.
 * Star Coin 3 - Right after the second Star Coin is a long stretch of rope. Near the middle of the rope is a Warp Pipe located on the ceiling. Using the rope, jump to the ceiling and go in the warp pipe to obtain the last Star Coin.

Enemies

 * Dry Bones
 * Podoboo
 * Bowser (boss)