From the Super Mario Wiki
Retrieved from "http://www.mariowiki.com/index.php?title=Door&oldid=1909275"
Doors appear at the end of any level in Mario vs. Donkey Kong 2: March of the Minis, Mario vs. Donkey Kong: Minis March Again! and Mario vs. Donkey Kong: Mini-Land Mayhem!. Mini Marios enter these doors to end the level. They are yellow-colored with an "M" symbol in Mario vs. Donkey Kong 2: March of the Minis. In Mario vs. Donkey Kong: Minis March Again!, they received slight changes: The "M" symbol is absent, and the door got slight pink border. However, in Mario vs. Donkey Kong: Mini-Land Mayhem!, they got completely changed: In single-door levels, the door is red with golden border. Unlike the previous games, the door will be closed if the minis aren't brought in after each other in a small amount of time, trapping some minis behind. In multi-doors levels, the doors for Mini Mario, Mini Toad, Mini Peach, Mini Donkey Kong, and Mini Pauline are colored red, blue, pink, yellow and green, respectively. Each mini must be brought to its own door. Unlike levels with one Door, there is no time limit in between how long it takes for one mini to enter a door. The regular Doors and Mini Doors reappear with the same use along with a light green Mini Luigi door in Mario vs. Donkey Kong: Tipping Stars.