World 5-Castle is the castle level of World 5 in New Super Mario Bros..
Boss fight against Petey Piranha
This level has many conveyor belts that Mario must jump onto, some having Piranha Plants and Dry Bones on them. Along the way, Mario will find the first Star Coin. Later, Mario should see three conveyor belts with some Dry Bones moving along them, and even a spring. He should jump on the moving spring to get the second Star Coin. To get the last Star Coin, Mario should first notice that, after a Super Piranha Plant, there will be a block with a hole in the ceiling above it. Mario should run and jump to the block and then Wall Jump through the hole in the ceiling. When the player goes to the right, they will fall down. Go to the left to get the last Star Coin. After going through the double doors, Mario will find and face Petey Piranha. If Mario does not have a Fire Flower, he must wait for Petey to pound the ice and fall. Then, Mario must stomp on Petey three times to defeat him, thereby going to World 6. If Mini Mario beats Petey (by Ground Pounding him three times), he will go to World 7 instead.
- Star Coin 1 - After the first few sets of conveyor belts, the Star Coin is in plain sight, but Mario must get it quickly, because a Piranha Plant from a conveyor belt will fall near it.
- Star Coin 2 - In the area where the Dry Bones, Super Dry Bones, and springs come down on conveyor belts, Mario should wait for the spring to come. He should hop on it to get a boost to a Star Coin on a ledge.
- Star Coin 3 - After the midway point where there is a lone block and an opening in the ceiling, Mario should run and jump to it, and then Wall Jump to get on top of the ceiling. Mario can also use a spring from earlier in the level to jump into the opening. Once Mario is on the ceiling, he should run to the right side, and he will fall onto a conveyor with a Dry Bones and the Star Coin in sight.