The game starts out with Mario opening an amusement park called "Super Mini Mario World" (a possible reference to the Super NES game Super Mario World). At the grand opening of his park, he and Pauline were opening the park. When Donkey Kong saw her, he attempted to give her a Mini Donkey Kong toy as a gift, but she ignores it and takes the Mini Mario from Mario instead. Donkey Kong becomes enraged, and kidnaps Pauline, taking her into the amusement park. Mario, unable to follow, sends the Mini Marios to save her.
The gameplay consists of you using the stylus most of the time. Some times you'll drag objects over to the Mini Marios to help them get over something or get up to a higher ledge. You'll also need to press buttons with the stylus to possibly open a bridge, or make certain blocks disappear. To move the Mini Marios, you must swipe the stylus right or left to make them move in that direction. Other features are drawing a bridge, and other currently unknown things.
By going on the Nintendo Wifi Connection service, you can make Courses, then put them online for other people to download. Once someone downloads your course, you will get points, the more points you get, the more items you will be able to use in making courses. You can also rate each course to give the creator more points.