Room B-7 is the seventh course of the Basement in Mario vs. Donkey Kong: Minis March Again!. It is unlocked by earning 80 gold stars from previous levels. The theme of the course is reused from the boss battles of Mario vs. Donkey Kong 2: March of the Minis and is an arrangement of the track that plays in the first and fourth battles with Donkey Kong from Mario vs. Donkey Kong.
The course features two mini toys.
The course encompasses a large amount of elements arranged in a maze-like manner. One mini starts in the top left, while the other starts in the bottom right stuck behind a yellow gate. The Goal Door is located near the top right, also behind a yellow gate. Throughout the course, the player can only make use of three Pink Blocks and, due to certain circumstances, has to perform a specific series of actions to reach the goal with both minis, similarly to Room 4-SP+.
Since the mini at the bottom cannot initially advance anywhere, the player can only start the mini at the top. Immediately after initiation, the player has to use the limited amount of Pink Blocks available to help the toy cross a row of spikes. The toy will then fall onto a conveyor that has to be set to run to the left in order to progress, leading off the platform. There are spikes at the bottom, so the player has to place Pink Blocks on a grid to prevent the mini from falling on the spikes and to change its direction to the right. Soon after, the mini will encounter a Pink Block grid with two yellow Polterguys around it and spikes at the bottom; the player has to use Pink Blocks to direct the mini on the solid ground to the left. Afterwards, the mini will encounter a Yellow Spring that will bounce it to a Yellow Color Switch. Pressing it will open the gate in front of the mini at the bottom, allowing it to go outside, but will also close a yellow gate right behind the mini that has pressed the switch and trap it there.
From its starting position, the mini at the bottom will soon reach a sideways Pipe that leads further to the right. Shortly afterwards, the player has to help the mini cross a pit of spikes with the Pink Blocks in the stockpile and help it reach a Yellow Spring on the other side of the pit. The spring launches the toy a level above, from where the player yet again needs to use Pink Blocks to cross the mini to the other side of the spike pit to an extended yellow bridge. The bridge leads to the same grid for Pink Blocks with Polterguys encountered by the mini before; this time, the enemies are turned into solid blocks due to the Yellow Color Switch that was pressed previously, allowing the mini to climb up to a ledge with the aid of Pink Blocks. After crossing some spikes with Pink Blocks, the mini will tread on an extended bridge that leads into a yellow Split Pipe. The pipe will warp the toy to the top left, where the previous mini started; however, this time, after crossing the small row of spikes, the conveyor lower down has to be set to run to the right. It now leads to a grid where the player has to place Pink Blocks to guide the toy over some spikes, leading it to an abrupt fall into a short passage. The mini will then fall down a gap (caused by a retracted yellow bridge) and should land on some Pink Blocks that lead to a cyan Split Pipe on the right, which will warp the toy directly in front of a Yellow Color Switch in the top right. After pressing it, the gate that blocked the previous mini will open and allow it to escape. However, it also extends two gates around the area where the toy that has pressed the switch will shortly fall into, one of which blocks the access to the Goal Door.
The freed toy will now follow the same path with the sideways Pipe as the mini before it and reach the area at the right where it should cross the pit of spikes to the Yellow Spring. This time, after bouncing off the spring, the toy must be guided with Pink Blocks to the extended bridge upper to the left. After walking on the bridge, the mini will encounter a wall and turn back. The player will then have to use Pink Blocks yet again to guide the mini to the cyan Split Pipe in the opposite direction. Upon reaching and pressing the Yellow Color Switch in the top right, the gates around the enclosed mini will now open and allow access to the Goal Door. Next to the gate on the left, another gate will extend to change the direction of the minis to the Goal Door and allow them to clear the course.
Mini Mario Card
The Mini Mario Card is located above a yellow bridge leading onto some spikes on the right side of the level. It can only be collected in the second phase of the course, when the bridge is retracted and allows the mini to fall into the gap before it walks onto the spikes.
This is the only course in the game to feature two M-Tokens instead of only one.