Room B-5 is the fifth course of the Basement in Mario vs. Donkey Kong: Minis March Again!. It is unlocked by earning 70 silver stars or better from previous levels. The soundtrack of this course is based on the castle theme from Super Mario Bros. and was also used in Mario vs. Donkey Kong 2: March of the Minis as the soundtrack of Lava Dome.
The course features three mini toys.
The course has a tall layout and is divided by a wall into two sides, with an opening at the bottom. The minis start next to each other on top of some Pink Blocks on the left side of the course at the top. The Goal Door is located on the same level, but on the right side. The Pink Blocks must first be used to help the minis descend to the bottom, since the way down is too high to simply drop the minis from above, while avoiding obstacles such as Polterguys and the spikes at the bottom. Once the minis reach the bottom and enter the right side of the course, they have to be brought to the Goal Door at the top by using Pink Blocks and springs.
Mini Mario Card
The Mini Mario Card is located on a girder platform in the right portion of the level. To reach and collect it, a mini must bounce off the Blue Spring underneath it. At first, the Blue Spring can only be accessed from the left side via a Yellow Spring underneath, and the player can change the mini's direction immediately after the bounce using Pink Blocks, allowing the toy to collect the Mini Mario Card afterwards. Otherwise, the mini can be brought to the top of the course and then drop through the gap in the middle, landing on a Pink Block that should be placed by the player to lead to the card.